Merge pull request #692 from atm-maxime/develop

LDAP sync improvements
New: Function plimit of databases drivers accept -1 as value (it means
default value set into conf->liste_limit).
Merge branch 'develop' of https://github.com/Dolibarr/dolibarr.git into
develop

Conflicts:
	ChangeLog
LDAP : update user sync + add groups sync and users associated to group + add fetch by name on group class