Added support to ID3v2 tags versions closes #25
Fixed quoted ffmpeg arguments call using shlex for parsing ffmpeg call command
Added exception handling for tags and reorganized imports
Added tag metadata exceptions
Updated tests and added more exception handling
Updated tests for shorter tests for each assertion and updated data files
Merge .travis.yml changes from remote-tracking branch 'upstream/master'
Fixed id3v2_version that causes problems on debian machines
Merge pull request #26 from marcwebbie/master

Added support to ID3v2 tags versions closes #25