Fix regression #234
Only display nav links once.
Fix #235.  Update README.txt.
Fix #237.
Fix #241
Merge branch 'master' of https://github.com/DBezemer/moodle-theme_essential
Update README.txt for 2.7.7.
Fix #238
Merge branch 'master' of https://github.com/DBezemer/moodle-theme_essential
Merge remote-tracking branch 'upstream/master'