GPIO mapping could use reconsideration

There's not a lot of GPIOs that the Pi Zero has exposed (even less when using an ESP8266 for WiFi). However, the I2C header currently has one of the GPIOs shared with the IR header, and that's kinda cringe. In addition to that, a Type-C mod board will take one GPIO away from the I2C pin header with its INT, and I'd expect a Type-C port to be a relatively popular mod.