Cutscenes: Remove double warning

The warning will also be yielded by the FileParser.
Fix french translation.

According to
http://opengameart.org/forumtopic/bug-in-fr-translation
I changed the %d to %s
Merge pull request #558 from stefanbeller/master

Remove double warning from Cutscenes.
Merge remote-tracking branch 'flare-engine/master'