Author: Tim Hunt
MDL-20636 Question import, support for files in hints.
Also fix some minor bugs and unit tests.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=c73c98365b442d75673326e0aa8989f2b25fb363
http://github.com/moodle/moodle/commit/c73c98365b442d75673326e0aa8989f2b25fb363