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.
I'd propose you ignore the return value of `ws_connbuf_append()` and return `res`, which you get from the `read`. That way you have a chance to catch `read()` returning `-EAGAIN` (which means that no error occured but that there is just no data atm.)