Fix fatal error when installing payment module.
Fix tests for the new core changes for field names
Change fields on the payment entity to be plain strings.
Merge pull request #98 from joshuataylor/commerce-tests-fix

Fix tests for the new core changes for field names
Merge pull request #99 from Jbekker/fix-error-payment-installation

Fix error payment installation and change the fields to be plain strings
Update the exception namespaces for the intl library.