* 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
* 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
* Update to latest code signing recommendations
* Move HttpProtocolHandlerPlugin into separate file
* Dont add subject attributes if not provided by upstream. Also handle subprocess.TimeoutExpired raised during certificate generation. Instead of retries, we simply close the connection on timeout
* Remove plugin specific flag initialization methods for now
Abhinav Singh