Revert "eWay Rapid: Upgrade to 3.1"

This temporarily reverts commit e5e3fe0eb7ef13e3eb77fd568b48fdd457392551
so that eWay Rapid 3.0 users can continue to use the implementation.
Should be added back when there's a strategy for supporting both 3.0 and 3.1

Conflicts:
	CHANGELOG