Last changes in Raven-FS

Serverside:
- Some refactoring
- Impementation of FilesStore and FilesStoreCommands - still missing Sessions -
- Implementation of active Incoming Synchronization Queue
- Splitted ChangesController into 2 separated controllers, one for Filesystems and the other for Databases

Clientside:
- File tree view implementation 
- Implemented listeners for synchronization push notifications