Author: Cameron Ball
MDL-74592 tool_uploaduser: Add option to match on email
http://git.moodle.org/gw?p=moodle.git;a=commit;h=2e4410290485a4319cf22c7fc6fab801eb7d541c
http://github.com/moodle/moodle/commit/2e4410290485a4319cf22c7fc6fab801eb7d541c
+ 4.1 en [duplicateemail,tool_uploaduser]
+ 4.1 en [matchemail,tool_uploaduser]