No module named 'adafruit_mcp230xx'

[caternuson]

This is happening due to a refactor of the MCP230xx library.

A few issues have been opened in the MCP230xx repo:
adafruit/Adafruit_CircuitPython_MCP230xx#12
adafruit/Adafruit_CircuitPython_MCP230xx#15
but should be here.

PR #39 should fix this.

[caternuson]

Should be fixed by #39