(svn r11657) -Fix: show better error message when trying to convert rail
-Codechange: merge DoConvert functions into one, make test and exec runs the same for tunnels/bridges

(svn r11523) -Codechange: Move the CHANCE macros to core/random_func.cpp cause they depend on Random()
-Codechange: Convert the CHANCE macros to functions and rename them fitting to the naming style

(svn r11399) -Feature(ette): transparency settings can now be saved and thus remembered.
-Codechange: Wrap all transparency settings in accessors, hiding the implementation
-Change: Clicking "transparent building" menu will toggle Houses And Trees only. The other options can be used in the transparency gui.
Initial patch by Smatz (FS#1349), with some rework by BigBB and your humble servant.

(svn r11369) -Codechange [FS#1390]: changes some int to int8 in macros.h, as they describe a bit-position, which fits perfectly in an int8 (max 64) (skidd13)
-Codechange [FS#1390]: added consts in macros.h functions, so compilers can optimise better (skidd13)
-Codechange [FS#1390]: remove HAS_SINGLE_BIT, as COUNTBITS does the same (skidd13)

(svn r11005) -Codechange: move the tiletype specific terraforming checks to the functions for those tile types.
-Codechange: barren the rail grounds on terraforming.

(svn r10097) -Feature: Add support for articulated road vehicles, or callbacks 11 and 17 for
road vehicles for those who prefer the technical explanation.

(svn r9951) -Fix: slope check was incomplete when building road over tram track (and vice-versa)
-Fix: you could build a drive-through station over a sloped road/tram track

(svn r9846) -Codechange: introduced ZOOM_LVL_MIN and ZOOM_LVL_MAX for the obvious reasons
-Codechange: introduced ZOOM_LVL_DETAIL to show/remove details
-Codechange: changed << and >> operator with ZoomLevel to a simple wrapper (that in theory also allows zoom-in besides the current zoom-out)
-Fix r9845: missed some int -> ZoomLevel

(svn r9844) -Codechange: replace zoomlevel with an enum
-Codechange: use predefined enums for viewport zoomlevels

(svn r9371) -Feature: Add support for variable snow lines in the arctic climate, supplied
by newgrf files. When this is enabled forests cannot be built below the highest
snow line, and farms can't be built above it. Houses still use the
_opt.snow_line so they are all consistent, so to make them respect the snowline
you may want to use some newhouses features as well.

(svn r8876) -Fix

Replace tests with magic numbers by a simple extraction template for command parameters

(svn r8875) -Fix

Remove unnecessary EnsureNoVehicle() checks because they are
- pointless per se (f.e. there are no vehicles on house tiles)
- done again (f.e. using CMD_LANDSCAPE_CLEAR just a few lines later)

(svn r8852) -Fix (r8735): make the dynamite tool for drive through road stops as if it were removing a normal road tile (consider the local authority and such).
-Fix (r8735): remove drive through road stops on town owned roads when going bankrupt/being removed.

(svn r8128) -Codechange: Split sprite and palette remap into separate 32 bit values.
This lets us increase the sprite width from 14 to up to 29 bits,
effectively nulling the old sprite limit. Table changes in next commit.