[Shpick] Add Mobi parser
[Interfaces] use QImage for cover image in Book structure
[Shpick] add cover image parsing to EPub
[Shpick] update Fb2 parser to new QImage cover
[Shpick] update Mobi parser to new QImage cover
[Sphick Tests] add mobi test
[Shpick] update EPub parser
[Shpick] update Mobi parser