added support for all webhooks in 2013-08-13
removed some rails parameters from test data
added customer.card.* webhooks, which are not documented by stripe, but exist
more explicit definition of supported webhook types
added a way to deep merge attributes
fixed syntax typo in README
explicitly specify the merge method in the README
Merge pull request #1 from lehresman/master

added support for all webhooks in 2013-08-13 and deep merging