FIX: copy extrafields when creating order from propale and creating
invoice from order
check extrafields before inserting in DB
Fix: Conflicts and remove duplicate code
Merge pull request #2016 from altatof/3.5

FIX: copy extrafields when creating order from propale and creating
Merge remote-tracking branch 'origin/3.5' into 3.6
Merge remote-tracking branch 'origin/3.6' into 3.7

Conflicts:
	htdocs/core/class/commonobject.class.php
	htdocs/product/class/product.class.php