feat(server): wait for frameworks to load via q.all() before starting server

The API is to simply return a promise from a factory function, or use a promise as a value. The server will wait for the collection of frameworks to resolve before carrying on starting the server.

This is useful for when setup requires some asynchronous startup.

Currently, any Promise api which is interoperable with q may be used.

In addition to this feature, this CL also adds a set of callbacks to the server, via an object for the 3rd parameter. This is useful for test purposes, and enables the test case to run faster, by not waiting for the server to shut down via the second parameter.

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There are some design decisions here which you might not like, such as using `mockery` rather than creating test fixtures outside of the test, or adding an object of callbacks to the server opener to help with testing it (it might be nice to have for other reasons, like bonus logging points or something). And of course, the main changes might be restructured in different ways too. So let me know if there are any issues with it @vojtajina, I suspect you were thinking the CL would be a bit smaller and change fewer things, but testing it seemed like a good thing to do.

Closes #851