(svn r7451) -Fix (7372): GetNum(Towns|Industries) should return the actual number of towns and industries.
-Fix (6055): GetMax(Town|Industry)Index should not return the number of towns or industries - 1, but the size of the pool - 1.

(svn r7331) - Codechange: Rename all memory pool macro's and types to "old pool", so the new pool implementation can be committed alongside it.
- Codechange: Rename pool.[ch] to oldpool.[ch].

(svn r6965) -CodeChange : Add a climate bitmask member to IndutrySpec.
Removed a loop that used the array _build_industry_types for that purpose.

(svn r6930) -Codechange: Move industry name into IndustrySpec
-Codechange: member color_map is more related to random color, rename it as such

(svn r6904) -CodeChange : Cleanup of industry_cmd (Step-5).
Add member life_type to IndustrySpec and remove the now useless _industry_close_mode array

(svn r6156) -Codechange: DeleteIndustry removes an industry from the pool
-Codechange: DestroyIndustry is called by DeleteIndustry to remove all things where a industry depends on.
Last 2 changes to prepare for new pool system. Not pretty now, will be soon.

(svn r6058) -Fix: Get(Industry|Town)ArraySize could never return 0
Note: _total_towns and _total_industries willb e removed soon, so this 'hack' is okay, for now ;)

(svn r6055) -Codechange: added GetXXXArraySize, which returns HighestID + 1 (or, will do that).
It isn't the best name, but we couldn't find any better.
This unifies the pool-system even more.

(svn r6047) -Codechange: FOR_ALL now _only_ loops valid items, and skips invalid ones
-Codechange: use IsValidXXX where ever possible
Note: both changes to prepare for new pool system, which needs those changes.
For every pool there are 2 ugly lines, which will be removed when done
implementing new pool system.
Based on FS#13 by blathijs, partly implemented.

(svn r6005) -Cleanup: introduce IndustryID and use it
-Cleanup: use TownID and StationID for two instances of uint16

(svn r6001) -Feature: when removing a farm, his farmland is removed too (over time) (based on peter1138's patch, FS#82)
To make this to work, in older games farmland is removed on load, and replanted

(svn r5999) -Feature: change the original date format to a 32 bits format based at the year 0.
The game date subsystem now allows someone to start in the year 0 and continue
up to the year 5 000 000. However, you currently cannot build anything before
1920 as there is no newgrf support for dates before 1920 or after 2090 yet.

(svn r4614) CodeChange : Cleanup of industry_cmd (Step-4).
Removing the _industry_type_costs in favor of IndustrySpec.cost_multiplier;
In order to let industry_gui use the GetIndustrySpec accessor,
some structs had to be moved in industry.h

(svn r2962) - const correctness for all Get* functions and most Draw* functions that don't change their pointer parameters
- change a lot of byte player types to PlayerID
- beautify header files, same "#endif /* filename */" ending

(svn r1834) - Fix: NPF does not check the owner of its target, busses try to enter other players' depots. TODO
- Add: asserts to find the v->u.rail.track == 0 problem.
- Add: IsValidDepot(), IsValidTown(), IsValidSign(), IsValidVehicle(), IsValidStation()
- Add: GetTileOwner(), IsTileOwner()
- Codechange: Replaced IsShipDepotTile(), IsTrainDepotTile(), IsRoadDepotTile() by IsTileDepotType().
- Codechange: typedeffed the MAP_OWNERS as Owner. Should be used as variable type.
- Codechange: Replaced a few uint by TileIndex.

(svn r1771) -Add: Industries are now dynamic (up to 64k industries). Generating
1kx1k maps should now be much faster, and give more than just oil-stuff ;)

(svn r1407) -Codechange: changed a lot around _stations, _vehicles, _towns and _industries
(in prepare of dynamic arrays):
- DEREF_XXX is changed into GetXXX
- All direct call are directed via GetXXX
- struct Industry has now an index-field
- ENUM'd some stuff
- Replaced home built loops with FOR_ALL_XXX
- Added _stations_size, _vehicles_size, ... which gives the length of the
array (which will be dynamic in the near future)
- Changed lengtof(XXX) to _XXX_size (e.g. _stations_size)
- Removed all endof(XXX) (because mostly it was part of a FOR_ALL_XXX)
- Made the sort-functions of all 4 dynamic
- Made all 4 Initialize functions more of the same
- Some minor tab-fixing and stuff
(tnx to Tron for proof-reading my 100kb patch ;))

Note for all: please do NOT directly call _stations, _vehicles, _towns and
_industries, but use the right wrapper to access them. Thank you.
Ps: please also do not use 'v++', where v is of type Vehicle *.