Tests: raise 'slow testcase' threshold of mocha to 200ms
Example server: only try to push when it's an HTTP/2 connection.
HTTP tests: two new fallback tests.
Endpoint: using assertion for checking constructor parameters.
Endpoint tests: testing endpoint formatter.
Framer tests: testing bunyan formatter.
Stream tests: testin bunyan formatter.
Stream: do not check for connection level frames in _transition().
Stream: adding a new assertion
Stream tests: testing for invalid outgoing frames.