vali monica: refactored BookDetails to an @Embedable
vali monica: merged with masterl fixed BookFacadeImplTest
vali: extracted NotifyBookAvailableCommand for email sending from BookFacade
vali: renamed updateAvailabelCopies to updateNumberOfCopies; added some TODO for Rest naming urls
Monica: Null checks for all methods in BookFacade.
Monica: Remove hard coding of application url from Notify Command.
monica: merge ExtendBookDetailsScreen branch with master
monica vali: moved updateNumberOfCopies from Facade to Entity
monica vali: changed exception message for updateNumberOfCopies