Fixed typo in invoice object.  Customer was set to
same json field as Closed.  Changed it to json:customer.
fix failing CreatePlan test
Added statement description to charge object
Merge pull request #29 from Attendly/master

Added statement description to charge object
fixing plan_test.go invalid currency lowercase
Merge pull request #31 from wfreeman/master

fixing plan_test.go invalid currency lowercase
Merge pull request #24 from tdburke/master

Fixed typo in invoice object.
Merge remote-tracking branch 'upstream/master' into charge_metadata

Conflicts:
	charge.go