Don't move a file if it doesn't have to be
Add 'remove_extra_frames' processor

Removes extraneous frames from the track
Use `-a` instead of `-d` for an implicit dry run
convetions: Define usage of 'Mix' in the title
Store the raw value for Size field objects
Ignore empty invalid values
Save mutagen file _before_ calling save-callbacks

In case the save callback reloads the mutagen file
Update raw attribute in Size on sync
Rename 'raw' property in Size to 'packed'

When the attributes are changed update the packed value as well
Always repack Size, when only formatting values
Add album_artist field to MediaFile
Only remove frames where there are some to remove
Add big-ass conventions processor

This should be (read: will be) refactored into many different
processors. Perhapse we can immplement the idea of sub-processors which
would be cool
Add import command
Apply all processors for sync command
Pretty up output

Not final output, could definitely look nicer