Added README

README.md

+*twspy* is a standalone implementation of web sockets for Python.
+
+- The websocket.WebSocket class upgrades a regular socket to a web socket.
+- message.py contains classes that abstract messages sent over the socket.
+  Sent messages are automatically converted to frames, and received frames are
+  converted to messages. Fragmented messages are also supported.
+- The server.Server class can be used to support multiple clients to open a
+  web socket simultaneously in different threads, which is often desirable in
+  web-based applications.