Fixing edit work see BT#6916
Adding Database::escape_string() see https://support.chamilo.org/projects/chamilo-18/wiki/Security_issues
Improving the asignment tool, adding a new way to upload files when "templates" are loaded see BT#6916
Implementing new work student view see BT#6916
Implementing new work student adding score/status in student view see BT#6916
Adding the $_configuration['allow_my_files_link_in_homepage']  see BT#6977
Minor - removing white spaces, format code.
Minor - removing unused option see BT#6985
Minor - removing white spaces, format code.
Minor - removing white spaces, format code.
Group tool: Adding import/export categories and groups CSV see BT#6985
Script only available for teachers.
Minor - cleaning whitespaces.
Allowing adding course categories if option is on in configuration.php see BT#6195
Adding option delete group/categories not in file see BT#6985
Adding search form, adding tutors and members list in group overview see BT#6985
Minor - adding icon
Adding validation before sending to the Import::csv_reader() that throws php warnings ... see BT#6985
Minor - formatting code.
Fixing col order see BT#6994