Adds the library libafbwsc.so

This library is intended to be used by C clients to connect
to the binder and access to its fetures through the websocket.

An example of integration is given by afb-client-demo.c

It is known that it introduces an unwanted dependency to afb-common.
This is a temporary issue.

Change-Id: Ie0a395f116f6ee05679525a6399ef23ef245c944
Signed-off-by: José Bollo <jose.bollo@iot.bzh>