Translate key city growth routines to English.
More translation of simcity.cc and simcity.h -- also simplify code, use existing subroutines
Merge branch 'jp-devel-new' into pretty-cities
More translation and code cleanup in simcity.cc
Add building cluster number.  Store in "extra_data".
Modify storage mode for clusters information, change writer.  Implement clusters.
Behave responsibly -- add a 'getter' and use it
Compilation fix.  Buildings can now have "clusters=1,2" and will cluster with buildings which have "clusters=1" and "clusters=2".  Building clusters should now work!  Not tested yet.
Fix declarations in building_writer.cc
Tweak building clustering (make it stronger)
Tweak clustering factor again.
Merge branch 'jp-devel-fixes' into pretty-cities
Merge branch 'pretty-cities' of git://github.com/neroden/simutrans.git into 112.x-private-car-merge