Fix issue with add payment method API call.

The old parameters we were passing breaks for a number of use cases.
The new method has one root node of "payment_method".
Update changelog and upped version to 0.2.1.
Up the timeout.

There are rare times when a gateway can take a REALLY long time to
respond.  We don't want to timeout before that since the transaction
could complete and we wouldn't know the real result.
New version to release.