(Make them look better) [ci skip]

- Update version history doc
- Update README simplifying and adding version history link
- Bump version

Seems the GitHub RST parser wants the ? for the SVG file path. Weird.

- Increment version
- Add changes to version history

- Create an abstracted _trigger_write() method in base.AMQPChannel, connection.Connection, and io.IO
- Update code to use the _trigger_write() method
- Fix an edge case bug in rabbitpy.Connection using a self._write_trigger that is not assigned by using self._io.write_trigger

If getsockname is called against a box that is IPv6 instead of IPv4, it returns a 4 item tuple instead of 2

- Thanks to @bkjones for the Message.pprint inspiration!