BookFilter usage
Merge branch 'master' into ice-cream-sandwich
Merge branch 'ice-cream-sandwich' into yota2
synchronisation with intro branch
Merge branch 'master' into ice-cream-sandwich
Merge branch 'ice-cream-sandwich' into yota2
BookElement sizes
Merge branch 'master' into ice-cream-sandwich
Merge branch 'ice-cream-sandwich' into yota2