MDL-31860 mod_forum: add advanced grading feature to forum
MDL-31860 mod_forum: remove custom grading class
MDL-31860 mod_forum: Different method of changing available methods no grade string.
MDL-31860 mod_forum: add aggregate methods to UI
MDL-31860 mod_forum: Fix calls to grading manager and remove empty line from install.xml
Revert "add aggregate methods to UI"

This reverts commit cd384bfd1c7fa94cd5357c39bb4a51cf7667b180.

Conflicts:
	course/modedit.php
MDL-31860 mod_forum: add behat test
MDL-31860 mod_forum: coding guidline stuff