Version 0.4.0

Breaking Changes

• send_frame/2 is now synchronous and returns an error when connection is opening or closing.

Enhancements

• Added debug printing for the :sys module.
• Rework Conn.new to accept other protocols.
• Added an InvalidFrameError for frames unrecognized by Frame.encode_frame.
• Go through the disconnect cycle when there's an error while with the {:reply, frame, state} callback response.
• Send a close frame with the close code 1011 when there is an unexpected error. (Like an Exception in the middle of a callback)
• Add a more specific error when the :websockex application hasn't been started yet.
• Added a :name options for local registration.

Bug Fixes

• Fix a couple of places where the call stack wasn't being properly tail-call optimized.