added the rest of the v1.1 methods

Review and merge https://github.com/Crowdtilt/Business-BalancedPayments/pull/39 before you review this, so that the diff will look right.

This PR makes the v1.1 client have feature parity with the v1.0 one.
Can we please rename `_wrapper` to `unpack_response` or something a bit more specific?  Wrapper is very generic.