Merge pull request #356 from ivandrofly/patch-1.0

Patch 1.0
Update sr-Latn-RS.xml
Update sr-Cyrl-RS.xml
Correct fix for split (#355)... thx again kempniu :)
Merge pull request #357 from diomed/patch-1

Update sr-Latn-RS.xml
Merge pull request #358 from diomed/patch-2

Update sr-Cyrl-RS.xml
Added preview for export to image based format
Fix for batch convert with matroska sub
Fix for mks in batch convert
Export to image preview now tries to use screenshot from actual video