Update payment risk assessment, and fix broken specs. Fixes #4630
Ensure shipments are also destroyed when the order is emptied.

Conflicts:
	core/spec/models/spree/order_spec.rb
drop credit_cards first_name and last_name fields

It was intended for this to happen eventually.
It's been causing confusion for us and some others in a couple ways so it seems like a good time to drop them.

Fixes #4787
Loosened the version required for select2-rails.

This version of select2-rails relies on sprockets ~> 2.0.0 (via sass-rails) whereas rails (~>4.1.0) relies on sprockets-rails (~>2.0) which relies on sprockets (2.12.1). A later version of select2-rails removes the dependency on sass-rails, which fixes the dependency conflict.