use Perl instead of Java as a base language for JS files; rebase translations
French translation update
Merge pull request #404 from RaphaelRochet/master

French translation update
Update messages.po
Merge pull request #405 from Trottel/patch-2

Update messages.po
Updated german translation
Merge pull request #406 from HeikoAdams/master

Updated german translation
Update messages.po
Merge pull request #408 from Trottel/patch-3

Update messages.po
Updater: check whether system() is useable.

system() was disabled on my system for security reasons, but the
updater would just continue, only to find out that the tarball
hasn't been extracted.
Merge pull request #410 from bram85/master

Updater: check whether system() is useable.