task #768:
https://doliforge.org/tracker/?func=detail&aid=768&group_id=144 
task #769 :
https://doliforge.org/tracker/?func=detail&aid=769&group_id=144
[ task #769 ] WYSIWYG for user signature
Merge branch 'develop' of https://github.com/Dolibarr/dolibarr.git into develop
task #768
Taking account remark
https://github.com/FHenry/dolibarr/commit/1f5ebb594a0ef9fa00f8b613b7fd6fc791813819
Taking account remark on pull request
Merge pull request #752 from FHenry/develop

task #768  &  task #769