cant delete product type with products
only change the name of product type is  it doesnt have products
You can't change a variation's name if there are already products using it
The user can print invoices in PDF format form the sale show page
Fix variations tests
Merge pull request #44 from suyccom/print_invoices

The user can print invoices in PDF format from the sale show page
Merge remote-tracking branch 'origin/master' into acciones_pendientes_variations
add logic in model
Merge pull request #41 from suyccom/issue_10739_creacion_nuevo_producto

Acciones pendientes de product_types
Merge pull request #43 from suyccom/acciones_pendientes_variations

You can't change a variation's name if there are already products using it
fix conflicts