Implement a new backup/sync system

Boy this took a while. I added in a new "cloud" syncing system that is completely modular. Kinda. You can add more sync services by extending SyncAbstract. I would recommend taking a look at DropboxSync if you wanna implement your own. This hasn't been tested on Mac or Linux.

New language files:
common.restore=Restore
backup.tab.backup.tooltip=Create a Backup
backup.tab.restore.tooltip=Restore a backup
backup.tab.settings.tooltip=Edit settings
backup.dialog.title=Backup & Restore
backup.label.backupchoose=Choose world to backup
backup.label.restorechoose=Choose backup to restore
backup.message.backupname=Enter a name for the backup
backup.message.backupname.title=Backup Name
backup.message.backupfailed.missingdirectory=Unable to find the correct save directory for the backup!
backup.message.backupfailed.title=Backup Failed
backup.message.deleteconfirm=Deleting a backup is not reversible! Are you sure you wish to delete %s?
backup.message.deleteconfirm.title=Delete Confirm
backup.label.autobackup=Auto Backup
backup.label.autobackup.tooltip=Whether a backup should be created on instance close
backup.label.notify=Popup on Success
backup.label.notify.tooltip=Create a notification dialog if a backup or restore has been successfully done
backup.message.backupexists=A backup with the name %s already exists!
backup.message.backupexists.title=Backup Already Exists
backup.message.backupfailed=Failed to create the backup!
backup.message.backupoverwrite=A folder with the name %s already exists. Are you sure you wish to overwrite?
backup.message.backupoverwrite.title=Confirm Overwrite
backup.message.restoresuccess=Restoration complete!
backup.message.restoresuccess.title=Restore Success
dropbox.notfound.title=Dropbox Folder Not Found
dropbox.button.location=Choose Dropbox location
dropbox.label.location=Please select Dropbox folder