Allow data uri scheme see #6814
Improving query, fixing PHP warnings.
Merge
Minor - format code.
Minor - format code.
Minor - format code, adding docs, removing using global $_configuration
Minor - format code
Adding missing $now variable.
Fixing PHP warning

ref 9648c1f1f7fa79930d30adfc426a93964efd7aa7
Minor  - format code
Minor - format code.
campo puntaje total BT#7159
Merge branch '1.9.x' of github.com:chamilo/chamilo-lms into nuevo
Minor - fixing PHP warnings.
Groups changes see BT#7156

Adding event_system (important activities) in group class add/delete/user_subscribe/user_unsubscribe,
adding 'allow_members_leave_group' option, require DB change
if the column does not exists the option returns 1 (users can leave groups default behaviour).
changing form class so it looks pretty
Minor javascript, missing function closure
translation of exercise.status in admin reports
autowidth for admin reports
Updated some language variables to make them more global-tolerant - refs BT#7149