feat($httpBackend): add timeout support for JSONP requests

Documentation implies that timeout works for all requests, though it
only works with XHR. To implement:
- Change $httpBackend to set a timeout for JSONP requests which will
immediately resolve the request when fired.
- Cancel the timeout when requests are completed.
fix(ngController): allow dots in a controller name

The issue was introduced in cd38cbf975b501d846e6149d1d993972a1af0053
test(controller): instantiate controller defined on window

Just adding a missing spec.