changed generate_order_number method for insure that generated numbers never finish #5102
Fix broken specs from order number refactoring, and improve performance. Fixes #5102
Fix payment state in order importer. Fixes #5109
Allow assigning source_id and source_type rather than creating a new source.

Conflicts:
	core/lib/spree/permitted_attributes.rb
Revert "Allow assigning source_id and source_type rather than creating a new source."

This reverts commit 70de4094d3d5e53d35c52f8eb25b630429481cbd.
Use rand(10) to cover all digits 0-9. Fixes #5113