Replaced/added the null logo to the boards.

Added more legend silkscreen to ears.

Fixed pin header 3d models. We had some of the models doubled up or not fully disabled. Now the TH pin headers are all using KiCad V5 3d model locations and are all disabled. This fixes #23

Updated 3d models to step, and new libs.

Added USB pads for easier debugging and hardwired USB connection. This patch fixes #8

Fixed #6 Oscillator pinout and schematic symbol. Both bitsy and icebreaker.

Started V0.2a of icebreaker bitsy.