(An_dz/dwachs) translate comments

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6671 8aca7d54-2c30-db11-9de9-000461428c89
(An_dz) translate/improve comments

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6672 8aca7d54-2c30-db11-9de9-000461428c89
(An_dz) translate/improve comments

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6673 8aca7d54-2c30-db11-9de9-000461428c89
CODE: rename calc_akt_speed to calc_friction to reflect its purpose

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6674 8aca7d54-2c30-db11-9de9-000461428c89
Fixed documentation error.

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6675 8aca7d54-2c30-db11-9de9-000461428c89
add some const

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6676 8aca7d54-2c30-db11-9de9-000461428c89
.. and compile again

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6677 8aca7d54-2c30-db11-9de9-000461428c89
FIX: lower/raise tools check all affected tiles whether scenario allows terraforming them

git-svn-id: svn://tron.homeunix.org/simutrans/simutrans/trunk@6678 8aca7d54-2c30-db11-9de9-000461428c89