Added construction of SynchronizeFolderOperation to OperationService
Refactored OperationsService to hold two separated Handlers in two separated worker threads, one for SyncFolder, one for the rest
Fixed access to storage manager in SynchronizeFolderOperation
Fixed compilation error
Merge pull request #797 from owncloud/download_folder__in_a_separate_worker_thread

Download folder  in a separate worker thread