Add basic support for native node_modules.

I pulled the commit from https://github.com/fdecampredon/jest/commit/c1089098324a6e44b4d78013a4410a2f00b6b8f9 and added a test. I added a test node_native module from https://github.com/kkaefer/node-cpp-modules. It is a binary which is kind of icky but it is also very small so hopefully that is ok. This should resolve #128 and #188.
This comment is misleading. `requireMock` actually calls through to `requireModule`, so they should be able to be mocked!