Fixing access error messsage -refs #6768
Remove disabled teachers from list of session course coaches - refs BT#7968
Fixing bug sending notification -refs #6909
Merge pull request #263 from ycastillo/fixes.6909

Fixes.6909
Merge pull request #262 from ycastillo/yoselyn.6768

Fix error page when clicking on an exercise's direct link and the exercise doesn't exist - refs #6768
Merge pull request #50 from chamilo/1.9.x

1.9.x