PiGRRL Zero with audio, more switches and a stronger case

This is a bottom case for an Adafruit PiGRRL Zero game console. It is entirely compatible with the default top case and has the following improvement:

• slots for a 28mm diameter speaker (https://www.adafruit.com/product/1890)
• mounting brackets for an audio amplifier (https://www.adafruit.com/product/2130)
• two more holes for on/off switch, labelled for airplane mode and audio on/off
• power icon next to the main switch
• stronger joints for a better connection (from the SNEAKxxATTACK remix), except on the back side of the case (to make it easier to close and fit between the case and the Raspberry Pi).

Note that, in addition to the audio amplifier, you will also need a low-pass filter (see https://learn.adafruit.com/adding-basic-audio-ouput-to-raspberry-pi-zero/pi-zero-pwm-audio). There is enough space at the bottom of the case for it.

Post-Printing

If you're using the plastic washers from the Adafruit project to hold the screen screws, then you will need to cut them on the side of the joint (otherwise the stronger joint is to thick to fit there).

You will probably also need to scrape some plastic on top of the micro-USB port. I did not make the joint thinner there because I find that the excess plastic is useful to get a tight fit for the Powerboost board.

Added support for more physical switches to the case (by default labelled for airplane mode and sound on/off), added opening and supports for a small audio-amp and integrated speaker. Merged the whole thing with the beefier joint case (but made it less beefier in some place to easy the assembly).