Re-enabled CloseApplication method.

Un-commented the clearing of GamesToBackup in the
Added initializing statements for dictionaries and added directory checking to the SetUpPollAutobackup method..

Changed SetupPollAutobackup return type to BackupResultHelper. Going to redesign StartBackup to take a
Made ComputeSourceHashes correctly return true
Made Backup.StartBackup
Since Scanner is only called when the target directory has files to compare with hashing, it now only runs if targetFiles contains files. targetFiles will only contain files