labels work as other book properties
TODO
Merge branch 'master' into ice-cream-sandwich
synchronization with master branch
Merge branch 'master' into beta

Conflicts:
	src/org/geometerplus/fbreader/book/BookCollection.java
Merge branch 'beta' into beta-ics
Merge branch 'ice-cream-sandwich' into beta-ics
code simplification
Merge branch 'master' into ice-cream-sandwich
Merge branch 'master' into beta
Merge branch 'beta' into beta-ics
Merge branch 'ice-cream-sandwich' into beta-ics
Query -> BookQuery
BookmarkQuery
Merge branch 'master' into ice-cream-sandwich
Merge branch 'master' into beta
Merge branch 'beta' into beta-ics
Merge branch 'ice-cream-sandwich' into beta-ics
Filter.HasBookmark + fixed book loading
Merge branch 'master' into ice-cream-sandwich