MDL-22236 Webservice file upload - Allow webservice file uploads direct to a draft filearea.

Via post to /webservice/upload.php
MDL-37148 Assignment: Lots of webservices

Conflicts:

	mod/assign/version.php
MDL-37148 Assign webservices: Easy ones !
MDL-37148 Assignment webservices : Implemented save_submission (with files)