Added HTTP Response Interceptor - PR # 2 for TP 23810

@tsanko @hippee-lee @kevinsproles This PR introduces the concept of an HTTP Response Interceptor which kicks in if there is an error in the HTTP calls, and raises an event on the rootScope if it is an HTTP 500 error. I also added a header to the individual $resource object so that it can be passed along with the event, so that the listener (theme) can decide what to do based on the "resource" header value.