Change renaming of duplicate files from file.ext-->file.ext.1 to file.ext-->file.1.ext

Works better when encountering multiple rar/par sets with identically named files.
Prevent further pauses by "unwanted extension", once the user has resumed the job after the first stop.

Part of this code was accidentally included in commit 081010d50beb9311e4c84889e5357305e9c4e12b
This is the missing part.
Merge remote-tracking branch 'upstream/0.7.x' into 0.7.x