Add local copy of resistor array footprint. To be removed when accepted upstream.

Update libfx2.

Move the USB connector flush with the board outline.

Moved USB connector to be flush with board edge. Added cutout for connector flange.

Make a few cosmetic changes to the PCB, both traces and silk. Also, actually connect ~OEQ pullup.

Add slew rate control resistors to DUT busses. Closes #35.

Add IFCLK test point. Closes #40.

Fix silkscreen issues with resistors moved to top. Closes #19 (again).

Implement basic FX2 bus arbiter (no starvation prevention yet).

Configure SLRD and SLWR as active low to avoid glitches.