Fix subconvert.desktop
Update Subconvert version
Added spin box for editing subtitle start and end.

It's spinbox and delegate job now to validate user input and pass it (or an error flag) to
SubtitleEditor. If user entered incorrect time start/end, SubtitleEditor will change appropriate
item background to red for ~1.5 second.
Code cleanup
Fixed problem with MOVIE_EXTENSIONS exception.
Use FPS from pfile when auto detection is unsuccessfull.

FPS value stored in spf file is preferred to some hardcoded value. Hardcoded FPS should only be used
when no other option is available.
Fixed incorrect parsing of multiple formats with header.
Added missing icons.
Fix installing icons

* Moved icons to a separate directory
* Added 16x16 and 22x22 icons
* Added logo.png in img directory (previously 256x256 subconvert.png)
* Icons are installed into hicolor and pixmaps
Moved img and test directories to the root.