fixed backer spec with locale problems
removed user credits field. It has not been used for while since we started calculating credits dynamically
rewrote for clarity
replaced some useless code for inherited_resources helpers adn rewrote checkout as credits_checkout to better reflect the method usage
renamed checkout to credits_checkout in project/backers controller for clarity
added specs to thank you action in projects/backers controller and moved its route so it receives the id of the backer. lets get rid of those nasty session variables