revC3: export fabrication files. Except for BOM.

revC3: update fabrication layer text size/position.

revC3: Corrected U2 (CAT24M01) part number.

revC3: Final cleanups before production. * Changed 3D models to step so the 3D model can be exported for enclosure CAD. * Changed silk and stop colors to match 1BitSquared production boards

Added null logo footprints to local library.

revC3: Corrected the USB-C 3D model position.

revC3: Added paste to USB-C shield anchors.

revC3: Hid U12&U21 labels. Corrected APX 1b2 key.

revC3: Increased Serial No frame size. Now the frame is >6mm wide which will accomodate some more common label printer labels without looking strange or oversized.

revC3: Increased min pad gap to 0.22mm. This increases the chances of getting solder mask bridges between pads decreasing probability of bridging.