added utils function to add "openid." to all properties in an object

added function to get all fields in an object prefixed with "openid."

created utils test file and added tests for the two functions

fixed response tests so they correctly test objects

created a placeholder in the response object for a fromURL function which
is equivalent to the fromForm class function.
placeholder tests for these functions have been created
implemented Response class function fromURL()
added tests for the Response class functions fromURL() and fromForm()