Merge pull request #4 from onijim/image_controller

Create images serializer class, add application helper for rendering jso...
Add JSON test helper to dry up the JSON parsing.
Merge pull request #5 from onijim/json_helper

Add JSON test helper to dry up the JSON parsing.
Test refactoring, plus tests and code for Image#show action
More ImageControllerSpec refactoring
ImageController#create method for creating an image from passed in attributes.  Also, some test refactoring
Basic implementation of ImagesController#destroy