ROADMAP: http2 tests are merged, mention http2 perf

HTTP/2

------

- test suite

   Base this on existing nghttp2 server to start with to make functional

   tests. Later on we can adopt that code or work with nghttp2 to provide ways

   to have the http2 server respond with broken responses to make sure we deal

   with that nicely as well.

   To decide: if we need to bundle parts of the nghttp2 stuff that probably

   won't be shipped by many distros.

Improve performance. Measurements and tests have shown that in several cases

doing transfers over HTTP/2 can be notably slower than the same transfer done

over HTTP/1. Some of that difference can be attributed the inefficient window

size handling currently in use but there are probably more to be learned and

worked on to optimize this.

HTTP cookies

------------