(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 r6406) -Codechange: Rename TileOffsByDir to TileOffsByDiagDir because it accepts
DiagDirections, and add TileOffsByDir that handles Directions.
-Codechange: Make the treeloop use TileOffsByDir().

(svn r6381) -Cleanup: make the '/* */' comments that span multiple lines more uniform.
-Cleanup: whitespace alignment of a few tables.

(svn r5136) Fix various style bugs:
- Trailing whitespace
- Trailing empty lines
- Missing newline at EOF
- Missing svn:eol-style native

(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.