Check if popup messages are enabled

Add a check to see if the popup message output is enabled before outputting a link to messaging in the custom menu
Merge branch 'hide_msgnav_when_messaging_disabled' of github.com:thedannywahl/moodle-theme_elegance into hide_msgnav_when_messaging_disabled

Conflicts:
	renderers/core_renderer.php
strip merge message

lol, I still suck at git.