Expose Mocks or Mocking functionality

[mollymorphic]

Clients consuming the library will presumably want to write tests validating their logic around using the data obtained from Surf-N-Perf. Since Surf-N-Perf presumably needs to mock the underlying browsers apis, etc for it's own use it would be nice to explicitly and cleanly expose these to clients for their own testing so they don't need to re-roll their own.

This could be in the form of just exposing mock data or providing functions to generate mocks based on some seed.