Rename self.client to self.request, in preparation for merging pull
request #72. The standard Python SocketServer/BaseRequestHandler
requires this name.
Rename new_client to new_websocket_client, in order to have a better
name in the SocketServer/HTTPServer request handler hierarchy. Prepare
for merge pull request #72. This work has been picked out of
7b3dd8a6f5ef26dbfd6c34a91600ea1613aefaa2 .
Merge pull request #110 from astrand/rename-self-client

Rename self.client and new_client - prepare for #72 / #111