Create :payment_authorized state for Contribution
Remove explicit state names on StateMachines

Default state values are already state names.
Fix typo on Contribution's state name
Remove extra blank line
Remove unnecessary comment
Improve indentation of code

Conflicts:
	app/models/concerns/project/state_machine_handler.rb
Merge pull request #124 from neighborly/im-payment-authorized-state-for-contributions

Create :payment_authorized state for Contributions