Optimized background display, improves performance lost to my previous patch.

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6430 8aca7d54-2c30-db11-9de9-000461428c89
CODE: get rid of some unused height-scaling macros

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6431 8aca7d54-2c30-db11-9de9-000461428c89
remove unused variables

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6432 8aca7d54-2c30-db11-9de9-000461428c89
squelch signed-unsigned comparison warnings

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6433 8aca7d54-2c30-db11-9de9-000461428c89
Make karte_t::move_cursor compatible with DOUBLE_GROUNDS

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6434 8aca7d54-2c30-db11-9de9-000461428c89
fix to last update.

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6435 8aca7d54-2c30-db11-9de9-000461428c89
CHG: use finer granularity to check for no activity as we have history for 24 months now

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6436 8aca7d54-2c30-db11-9de9-000461428c89
CHG: increase limits for remove_dummy_player_months / unprotect_abondoned_player_months

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6437 8aca7d54-2c30-db11-9de9-000461428c89
FIX: check for valid pointers in exported functions

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6438 8aca7d54-2c30-db11-9de9-000461428c89
FIX crash when deleting tunnel tile

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6439 8aca7d54-2c30-db11-9de9-000461428c89
FIX: crash when building powertunnel

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6440 8aca7d54-2c30-db11-9de9-000461428c89
FIX: maintenance when removing tunnel tiles

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6441 8aca7d54-2c30-db11-9de9-000461428c89
CHG: Added a new setting to simuconf.tab, background_color. 

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6442 8aca7d54-2c30-db11-9de9-000461428c89
Thai character in cyr.bdf

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6443 8aca7d54-2c30-db11-9de9-000461428c89
Add missing files to project

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6444 8aca7d54-2c30-db11-9de9-000461428c89
force world redraw on window resize.

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6445 8aca7d54-2c30-db11-9de9-000461428c89
FIX: map borders on DOUBLE_GROUNDS

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6446 8aca7d54-2c30-db11-9de9-000461428c89
missing newlines

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6447 8aca7d54-2c30-db11-9de9-000461428c89
FIX: coordinates to jump to places on the map were not rotated correctly

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6448 8aca7d54-2c30-db11-9de9-000461428c89
Display of thai font. But cry.bdf is anyway with wrong offsets

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6449 8aca7d54-2c30-db11-9de9-000461428c89