Remane contract ref_ext to ref_supplier
changelog
Merge branch 'develop' of git@github.com:Dolibarr/dolibarr.git into
develop

Conflicts:
	ChangeLog
	htdocs/install/mysql/migration/3.6.0-3.7.0.sql
Add a real free numbering module for contract
Enable supplier price log table
Fix Travis
fix travis
Merge pull request #1760 from FHenry/develop

Remane contract ref_ext to ref_supplier