Add "Upload all now" option to scan and back up files missing from the remote directory

Currently I can select the folders I want to be monitored but I can't make it check and upload files not currently in the corresponding server directory.

As a stop-gap for true two way sync it'd be nice to have an option in folder settings (where the directory, upload on WiFi only, etc are set) to scan and backup now any files not in the set remote directory.

This may be a good permanent solution for one way sync (which I assume will always be present as an option) also.