introduced AndroidImageSynchronizer
Merge branch 'master' into beta

Conflicts:
	src/org/geometerplus/android/fbreader/library/BookInfoActivity.java
conections pool
Merge branch 'master' into beta
refactoring: PluginConnectionPool => AndroidImageSynchronizer
simplification: PluginMetainfoReaderImpl & AndroidImageSynchronizer merged into one class
imports
Merge branch 'master' into beta
ZLLoadableImage.Synchronizer passed to ZLLoadableImage.synchronize() method
Merge branch 'master' into beta

Conflicts:
	src/org/geometerplus/fbreader/formats/external/PluginImage.java
MetaInfoUtil.PMIReader field has gone
cosmetics
Merge branch 'master' into beta
method synchronizeFast() still used
Merge branch 'master' into beta
method ZLLoadableImage.synchronizeFast() has gone
Merge branch 'master' into beta