Merge remote-tracking branch 'origin/3.3' into 3.3_backported

Conflicts:
	htdocs/compta/facture/impayees.php
Merge remote-tracking branch 'origin/3.3' into 3.3_backported
Prepare for option MAIN_GENERATE_PROPOSALS_WITH_PICTURE
Merge remote-tracking branch 'origin/3.3' into 3.3_backported
Merge remote-tracking branch 'origin/3.3' into 3.3_backported
New: Can show images of product onto proposals.

Conflicts:
	htdocs/core/modules/propale/doc/pdf_azur.modules.php
Merge remote-tracking branch 'origin/3.3_backported' into 3.4_backported