Adding tables in order to implement the "session path".
SQL changes.

Adding changing varchar size default_event_type/default_value_type and
adding usergroup.allow_members_leave_group.
Adding c_group_info.iid
Changing "text" with "longtext".

See https://support.chamilo.org/issues/6814
Merge branch 'master' of github.com:chamilo/chash