FIX: gui chart x-axis labels with left_to_right_graphs set

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6544 8aca7d54-2c30-db11-9de9-000461428c89
(kierongreen) FIX: wrong bridge slope images displayed

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6545 8aca7d54-2c30-db11-9de9-000461428c89
(kierongreen) FIX: vanishing elevated ways upon loading

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6546 8aca7d54-2c30-db11-9de9-000461428c89
FIX: crash building powerline bridge up cliff

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6547 8aca7d54-2c30-db11-9de9-000461428c89
FIX: sanity check user input pak path - must exist below program dir

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6548 8aca7d54-2c30-db11-9de9-000461428c89