(svn r8807) -Feature: Add support for loading (some of) the TTDP extra chunks mainly list of GRFIDs and TTDP version the game was saved with.
GRFID list is read and active GRFs are loaded with the game if present in the data/ directory.
TTDP versioning information only works for newer versions, old versions will only give rough information but it's not worth the effort to precisely figure out what bit means what where and when.

(svn r8660) -Fix

-Codechange: Remove _avail_aircraft
Its name is misleading. It is rather _avail_airports, but then only some of them, which leads to inconsistencies when using it.
Further it is unnecessary to store it in savegams.

(svn r8477) -Fix

-Codechange: Remove the unnecessary attributes Station::{bus,lorry}_tile_obsolete by replacing them with a scan of the map for existing road stops when loading old savegames

(svn r8475) -Fix

Remove the unused remnants of blocked_months_obsolete

(svn r8385) -Fix

-Regression (r8314): I only did half the necessary changes to move railtype from Engine to RailVehicleInfo. Now do the rest.

(svn r8276) -Fix

Change the signature of Swap() to be less error prone, i.e. pass the variables to be swapped by reference instead of passing pointers to the variables.
Just do Swap(x, y) instead of Swap(&x, &y). This prevents accidents when the variables are pointers.

(svn r8207) -Fix

Remove the write-only attribute RoadStop::station

(svn r8071) -Fix (r5999): [FS#536] Merging 32bit dates broke the inauguration date of companies in
oldloader: "The year the company was inaugurated (full value, not base-1920)"
(Marcin Grzegorczyk's TTD internals site)

(svn r8050) -Codechange: Rename map member extra to m6, since its usage has been widden.
Only doc landscape_grid.html has been updated, landscape.html will be done latter.
-CodeChange: Replace a direct access to m6 with SetTropicZone in InitializeLandscape, as it is the only part of m6 still untouched without the brute-forced m6=0