Switch to tape for testing

I have strong feeling, that we have poor tests:

 * We test got against real hosts - it takes too much time
 * All tests are stored in one file
 * Not all cases are covered
 * Mocha is quite bloated, when `before` and `after` used

This PR porting parts of request tests (and ssl certificates). For now `test-requests.js` is hanging (because of no reason) - if someone sees problem, please point me at it.