Super IO Expander Support

[Gadgetoid]

Should replace #13

The Super IO Expander uses a Nuvoton MS51TC0AE, featuring 26 user controllable GPIO pins, most of which have special functions like ADC, PWM, and encoder counting.

In addition this PR adds classes to make it easier to interact with motors, servos, and encoders connected to both the new and existing IO Expander.

[coveralls]

Pull Request Test Coverage Report for Build 4628874056

• 679 of 971 (69.93%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-2.3%) to 73.038%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
ioexpander/init.py	287	579	49.57%
<!--	Total:	679	971	69.93%	-->

Totals
Change from base Build 1958068705:	-2.3%
Covered Lines:	791
Relevant Lines:	1083

---

💛 - Coveralls

[ZodiusInfuser]

I think this is about as good as it can be. Documentation can be improved, but I will do that as a separate PR