Revised Bunny Shaped Enclosure for µIEC

some modifications to tml's [Bunny shaped enclosure for uIEC](https://www.thingiverse.com/thing:105337) to allow for new button placement and additional connectors in the latest hardware revision from [RETRO Innovations](http://store.go4retro.com/uiec-sd/ "RETRO Innovations"). This is not a very elegant modification:

* the SIP connector slots could be a bit taller

* the USB power connector could be moved a bit.