* Create overlay branch.
Merge remote-tracking branch 'remotes/origin/master' into overlays
 * Added singe and multi color overlay support.
Remove cell_pathfinding compatibility layer as indicated by comment

Partically reverts 6bf7d2d902af27f632e1835cdcde287469141129 on this file.
Use integer divisions in some pychan calculations

All size and position attributes are integers, so this is one of the
smallest steps towards python3 support of any kind. It also is one of
the lowest-hanging.

Fixes some coding style issues related to whitespace on the way, and
clarifies some operations as well by adding parens (keeping semantics).
Replace C++ license headers referring to `fifengine.de` with `.net`

One more time.
Replace python license headers referring to `fifengine.de` with `.net`

Also caught some bash in the process apparently.
Merge pull request #774 from fifengine/fifengine-net

Replace license headers referring to `fifengine.de` with `.net`
Fixing various links
Removing guichan from ext

This includes removing the ext option from scons.  fixes #771
 * Fixed facing location and a related bug. fixes #773
Merge pull request #776 from fifengine/int-divisions

Use integer divisions in some pychan calculations
Removed old wiki links
Removed old wiki links
local tinyxml files are now only added to the compile list if either --local-tinyxml is defined for SCons or the system version of tinyxml is not found. A warning is issued if the system version is not found. fixes #619
Possible fix. refs #777
Fixed the dates in all headers to read 2005-2013
Fixed improper spacing in file headers
 * Fixed the visible/invisible problem. fixes #780
 * Fixed hopefully the segmentation fault which is described here https://github.com/unknown-horizons/unknown-horizons/issues/1993