Merge pull request #20 from lepidum/unify-compressor-req-res

Unify request/response roles of Compressor/Decompressor
Framer updated for h2-14

- 24-bit frame size
- Default max frame size is 16384, not 16383
- Setting identifier is now 16-bit
- Remove PAD_HIGH, padding in CONTINUATION
- Allow extension frames, extension settings