Add ws connector 

targets #160 

This is what I figured from the specs.
I admit I'm not completely sure how this thing is gonna work (especially the flushing / the actual data transfer via outbuf).
But I wanted to do this in order to gain a better understanding of how stuff works, so I hope that's still alright...

I'm thankful for corrections and/or hints about which prototypes are still missing.
Please call `ws_connbuf_append()` once you reserved memory, so the connbuf is ""unblocked" before they return. (so you can call `ws_connbuf_reserve()` or `ws_connbuf_discard()`)