* Ensure pending buffers are flushed before shutting down in base_server.py
Handle unsupported scheme cases within connect_tunnel.py
* Move base implementations within core module
* Update ssl_echo_server
* Go flagless to allow custom user defined flags. Fixes#301
* Add --cache-dir flag for cache plugin (when used with on-disk store)
* Enable discovery of flags from external plugins, example those that reside outside of proxy.py package and loaded on demand. This also allows external flags to surface in --help section
* Define --filtered-client-ips flag for FilterByClientIpPlugin
* Move wrap_socket for SSL server within utils.
Also complete proxy.common.pki gen_csr and sign_csr actions. Used by Makefile sign-https-certificates.
* Add SSL echo server and client example
* Add examples documentation
* Move wrap functionality within respective connection classes. Also decouple websocket client handshake method
* Add a TCP echo client example that works with TCP echo server example
* Better document acceptor module and add a TCP Echo Server example
* autopep8 formating
* Rename ThreadlessWork --> Work class
* Make initialize, is_inactive and shutdown as optional interface methods.
Also introduce Readables & Writables custom types.
* Move websocket code into its own module
* Add websocket client example
* Cleanup websocket client
Abhinav Singh