[ task #1204 ] Add ref_int contract field
Allow trigger call on update line (class ContratLine must extends
CommonObject to have method call_trigger)
Merge branch 'develop' of git@github.com:Dolibarr/dolibarr.git into
develop

Conflicts:
	ChangeLog
Use good translation
Merge branch 'develop' of git@github.com:Dolibarr/dolibarr.git into develop
chnagelog
Merge pull request #1731 from FHenry/develop

[ task #1204 ] Add ref_ext contract field