Adding addAnnouncementToAllUsersInSessions option see BT#7217
Adding send_email for all users in al session see BT#7217
Remove option to send announcements to all sessions if we're in a session - refs BT#7217
Add id_session to e-mail link-to-announcement to avoid access errors - refs BT#7217
Merge branch '1.9.x' of github.com:chamilo/chamilo-lms into 1.9.x
Documentation and code cleaning - refs BT#7017
Moved function get_exercise_progress() out of SessionManager class and into Tracking class - refs BT#7017
Vastly improve performance on exercise_progress report + fix missing data issue - refs BT#7017
Resolve minor visual issue with exercise name in select box - refs BT#7017
Resolve visual issue not showing the right quiz name - refs BT#7017
Resolve minor visual issue with exercise name in select box - refs BT#7017
Add encoding switch for XLS export - refs BT#7017
Add browser platform checker for encoding decision - refs BT#7017
Encoding change is only necessary for Windows - refs BT#7017
Add students list to courses export - refs #6904
Minor code spacing changes
Merge remote-tracking branch 'upstream/1.9.x' into 1.9.x