(svn r7195) -Feature: [FS#297, optional elrails] New patches/vehicles option 'disable electrified railways'.
(original patch by maedhros, ideas: peter1138, Darkvater, Rubidium, Patrick, Eddi|zuHause, ..)

(svn r7028) -Fix [FS#200]: Scenario bridges/tunnels cannot be demolished; now it's possible to
delete tunnels/bridges owned by nobody.

(svn r6776) -Codechange: Use IsValidPlayer() function to determine of a PlayerID is an
actual playable player (< MAX_PLAYERS) or not.

(svn r6775) -Codechange: Use some more proper types, especially Owner and PlayerID as
these are used intermixed often.

(svn r6774) -Codechange: Rename the badly named OWNER_SPECTATOR to PLAYER_SPECTATOR and
put it into player.h where it belongs (instead of map.h)

(svn r6637) -Codechange: merged all (vehicle type)EnterDepot into VehicleEnterDepot()
This revealed duplicated code like aircraft lists got invalidated twice
Moved invalidation of the vehicle detail window to VehicleServiceInDepot() as it should always be updated when serviced

(svn r6513) -Codechange: unified the code to draw depot windows
This change is intended to make it easier to make depot behaviour consistent
and faster to code when adding more features in the future
The user interface should hopefully not be affected by this

(svn r6141) -Codechange: introduced DepotID and used it as much as possible
-Codechange: DeleteDepot removes a depot from the pool
-Codechange: DestroyDepot is called by DeleteDepot to remove all things where a depot depends on.
Last 2 changes to prepare for new pool system. Not pretty now, will be soon.
-Codechange: Removed DoDeleteDepot as it was stupid

(svn r6053) -Codechange: renamed all IsXXXIndex to IsValidXXXID
-Codechange: IsValidXXXID now also checks if XXX is really valid, not if the number is within range
Both changes again in preperation of the new mem-pool system, which requires this.
IsValidXXXID is not a bit less pretty, but that will be cleaned up after the new mem-pool system

(svn r5723) - Move the declaration of DrawRoadDepotSprite() out of functions.h (but I'm not too happy with the new header)
- Use DiagDirection instead of plain int for the orientation of the depot graphics
- Rename the associated data tables with sprites to something more meaningful

(svn r5396) - Remove two fixed parameters
- Simplify an expresssion: c ? f(x) : f(y) -> f(c ? x : y)

(svn r5315) -Fix: Prohibit altering a road tile while road works are in progress
This fixes some glitches like "turning" the excavation by adding/removing road bits or removing the road piece

(svn r5070) Merged the bridge branch
-Feature: Bridges can now be placed above:
Any railway track combination (excluding depots and waypoints)
Any road combination (excluding depots)
Clear tiles (duh), including fields
Tunnel entrances
Bridge heads

Thanks to Tron for idea and implementation, KUDr for the yapf synchronization and many others for hours of testing

There are still a number of visual problems remaining, especially when electric railways are on or under the bridge.
DO NOT REPORT THOSE BUGS FOR THE TIME BEING please.

(svn r4572) Remove vehicle_leave_tile_proc
There's exactly one implemented function (unbarring a level crossing) and one place where it can be triggered (a train leaves a level crossing)
It's a bit overkill, so just handle this one case where it can happen

(svn r4342) Change the first two parameters of commands - virtual pixel coordinates of the tile to operate on - to a TileIndex
Remove DoCommandByTile(), because now it does the same as DoCommand()

(svn r3686) Dispel some strange magic regarding level crossings and foundations:
if a level crossing is on a sloped tile, it has to be on a level foundation

(svn r3680) Fix some magic numbers which got damaged in r1768
-Fix: Correctly restore the roadside after roadworks are finished

(svn r3564) Several smaller changes:
- Don't treat non-booleans as booleans
- Reduce variable scope
- Bracing
- Use DeMorgan's law to make conditionals easier to read
- if cascade -> switch
- Replace some magic numbers by symbolic names
- Avoid assignments within other statements

(svn r3472) - [PBS] Remove from trunk. Anyone interested can still find it in branch/pbs. This reverts revisions r3158, r3140, r3075, r2977, r2674, r2625, r2621, r2529, r2528, r2525, r2524, r2519, r2517, r2516, r2507, r2499. (in conjunction with Tron)
- The only change is that the nsignalsw.grf file is kept and that existing nightlies with PBS signals get those signals converted to combo-signals.

(svn r3313) Remove GPMI related changes from trunk
Revisions in detail: 2542, 3226 (partial), 3229, 3231, 3232, 3238, 3242-3245, 3251, 3253, 3260, 3263, 3265, 3266, 3269, 3277, 3278, 3279, 3283 (partial), 3304, 3305, 3306