Use specified fps value in DataModel
SubFile fixes and improvements.
Restored CLI support + bunch of necessary fixes.

* SubtitleData has been moved to a separate module
* Added SubException as a base class for Subconvert specific exceptions
* Fixed incorrect logger instances
* SubFile throws exceptions on UnicodeDecodeErrors
* Added __appname__ to version file
* [TODO] Currently there is still no implementation for PropertyFiles in CLI mode.