don't update last_pushed_timestamps until batch push completes
Fixes #37
Source isnt always credit card. Fixes #26

Conflicts:
	spec/serializers/spree/wombat/customer_return_serializer_spec.rb
	spec/serializers/spree/wombat/inventory_unit_serializer_spec.rb
	spec/serializers/spree/wombat/refund_serializer_spec.rb
	spec/serializers/spree/wombat/reimbursement_serializer_spec.rb
	spec/serializers/spree/wombat/return_item_serializer_spec.rb
Name is optional as well.
make sure we serialize the id as well on the line_items since wombat requires at least an id on objects.
Add id for payment data
Fixes #41
Dont set order#placed_on unless completed_at present & add Order totals & billing address to shipment.

Conflicts:
	app/serializers/spree/wombat/shipment_serializer.rb
Shipments should serialize inventory units not line items.
sincronize with original repo