Experimental 0.3.x branch of WebSocket++

This branch really is experimental and should not be used as the basis for any
serious projects. Its API is likely to change rapidly in the next few weeks.

Complete:
- Server role passes all Autobahn v0.5.9 test suite tests strictly
- Handler API

Needs work:
- Logging
- Client role
- Extension support
- permessage_compress extension