Codechange: Rename TownEffect to TownAcceptanceEffect.

This makes it clearer that TownEffect only affects acceptance behaviour.

Codechange: Store Colours in Colours type. (#11625)

This reduces casts, some magic numbers, and introduces a bit of type-safety.

Codechange: Redefine some cargo-related values in terms of CargoID instead of CargoType.

Values used as special filter types are now defined as offsets from NUM_CARGO instead of confusingly reusing CARGO_NO_REFIT/CARGO_AUTO_REFIT types.

Codechange: Split CT_INVALID into CT_INVALID and INVALID_CARGO.

INVALID_CARGO is a CargoID and should be used for most purposes in game.
CT_INVALID is a CargoType used for defining default properties.

Fix: Changing default livery did not propagate to group liveries.

#11614 attempted to address this but did not handle 2CC properly, and changes to the default livery were not handled.

Codechange: Use consistent name for bay road stops

As of #10494, this is how we describe original dead-end road stops.

Codechange: Add base() method to StrongType to allow access to the base type without casting. (#11445)

This removes the ability to explicitly cast to the base type, but the requirement
to use .base() means the conversion is still explicit.

Change: Store station blocked/wires/pylons flags in map. (#11337)

This stores three flags in unused map bits, and avoids having to look up
station graphics and custom station specs to determine blocked/wires/pylons
status.

This potentially affects rail pathfinding performance.

Savegame version is not bumped, as the flags can just be updated every
time.

Codechange: make explicit when a TileIndex is cast to its basetype (#11190)

This prevents people accidentially assigning a TileIndex to a Date
or any other type they shouldn't.

Fix #10334: Store separate newgrf-safe version of date_of_last_service. (#11124)

This value is not changed when the date cheat is used, which caused issues with changing properties based on service date.

Co-authored-by: Peter Nelson <peter1138@openttd.org>

Codechange: automatic adding of _t to (u)int types, and WChar to char32_t

for i in `find src -type f|grep -v 3rdparty/fmt|grep -v 3rdparty/catch2|grep -v 3rdparty/opengl|grep -v stdafx.h`; do sed 's/uint16& /uint16 \&/g;s/int8\([ >*),;[]\)/int8_t\1/g;s/int16\([ >*),;[]\)/int16_t\1/g;s/int32\([ >*),;[]\)/int32_t\1/g;s/int64\([ >*),;[]\)/int64_t\1/g;s/ uint32(/ uint32_t(/g;s/_uint8_t/_uint8/;s/Uint8_t/Uint8/;s/ft_int64_t/ft_int64/g;s/uint64$/uint64_t/;s/WChar/char32_t/g;s/char32_t char32_t/char32_t WChar/' -i $i; done

Change: Reorganise industry accept/produce arrays. (#10853)

Use a array of struct for each cargo instead of an array for each statistic.
This makes iterating for acceptance and production much simpler.
pct_transported is now calculated when needed.

Codechange: Use IsValidCargoID/IsValidCargoType.

IsValidCargoType() is used only for unmapped IDs.

Feature: opt-in survey when exiting a game

On first start-up, the game will ask if you want to participate
in our automated survey. You have to opt-in, and can easily opt-out
(via the Options) at any time.

When opt-in, whenever you exit a game, a JSON blob will be send
to the survey server hosted by OpenTTD. This JSON blob contains
information that gives a global picture of the game just played:
- What settings were used
- How many humans vs AIs
- How long the game has been played
- Basic information about the OS / CPU

All this information is kept very generic, so there is no
chance we send private information to our survey server.
Nothing in the JSON blob could identify you as a person; it
mostly tells about the game played. At any time you can see
what the JSON blob includes, by pressing the "Preview Survey
Results" button in-game.

Codechange: Place gamelog into its own class, along with internal data.

Data is now stored in vectors to avoid manual memory management and
passing lengths around.

Codechange: Make SpriteType, CargoSortType, SourceType and ScriptType enum classes. (#10663)

This avoids a (soft) namespace conflict between the four ST_* enums.

Change: replace per-AI "start_date" with a global "competitors_interval" (#10653)

The per-AI "start_date" is a lot of custom code, and was rarely
used in the way it was meant.

While at it, also ported this part over to the new timer system.

Change: make GetPartialZ consistent, meaning Z of adjacent slopes continue

Previously, on a straight line of a one corner up slope with the adjacent
steep sloop the Z would increase one step every two sub pixels, except for one
case where one sub pixel is skipped. Similarly, a steep slope with two
adjacent one corner up slopes, would have a bump in the height line along the
diagonal whenever it enters/leaves the steep slope tile.

Codechange: pass "ground vehicle" to GetTileSlopeZ since for tunnel/bridges there are two states

Previously it checked the position in non-driving direction to "guess" whether
a ground vehicle was using the function, so on tunnels/bridges it could either
return the Z of the (virtual) ground compared to the Z of the path the vehicle
would take.

Feature: Separate rail/road and sea/air velocity units, and add knots. (#10594)

This is achieved by packing vehicle type along with the velocity so that
the string system can decode and pick the appropriate unit.

Codechange: introduce iterator to iterate over the Tiles of a Map

Note: this version is using TileIndex, but that changes later

Fix #10331: Starting new company during load must happen after AI start. (#10332)

This situation occurs when loading a savegame in single-player which only
has AI companies.

Codechange: using "until" in function names can be confusing

IsSavegameVersionUntil() did a [0, N] check, not [0, N) as the
name suggests.

Until can be a confusing word, where people consider it to be
including the upperbound. Dictionary states it means "before",
excluding the upperbound. There are long debates about who is right.

So, simply remove away from this ambiguity, and call it "before"
and "before or at". This makes the world easier for everyone.

Fix: compatible NewGRFs in crash-log reported wrong md5 (#9340)

The text suggests it reports the original md5, but it does in fact
report the replaced md5. Now it reports both.

Change: reworked the debug levels for network facility (#9251)

It now follows very simple rules:
0 - Fatal, user should know about this
1 - Error, but we are recovering
2 - Warning, wrong but okay if you don't know
3 - Info, information you might care about
4 -
5 - Debug #1 - High level debug messages
6 - Debug #2 - Low level debug messages
7 - Trace information

Change: rename setting "max_heightlevel" to "map_height_limit"

This better reflects what it is, and hopefully removes a bit of
the confusion people are having what this setting actually does.

Additionally, update the text on the setting to better inform
users what it is doing exactly, so they can make an educated
decision on how to change it.

Next commit will introduce an "auto" value, which should be the
new default. The rename has as added benefit that everyone will
start out on the "auto" value.

Fix 2fd871e2af5: load correct ending-year for old (pre 0.7) savegames

Despite what it looked like, you could never really change the
ending-year (it was always reset to 2050 on start-up). See commit
683b65ee1 for details. As a side-effect, the variable that was
suppose to store the ending-year was just zero, never containing
a real ending-year.

Fix: Incorrect save/load array size of Town::cargo_accepted

In 11ab3c4e the number of cargo types was changed from 32 to 64.
The save/load of Town::cargo_accepted was not updated, such that
only half of the data structure is saved/loaded in savegame versions
199 to 218.
Discard and regenerate data from all savegame versions prior to 219.