Dynamically update response objects

Now supporting dynamic response updates! Mimic the action of your back-end system simply by passing in a function to generate new response objects.

Full browser support

RequestMock is now functioning across all modern browsers, including Chrome, Firefox, and IE 11.
Returns mocked responses for mocked URLs and calls normal fetch/XHR for non-mocked URLs

v1.0.0 First release

First release of RequestMock! Everything is as described in ReadMe.md