Rev B

This update implements rev B of Titan (PCB and variant), including:

1. Increasing the ECP5 CSG324 footprint pad size to 0.34mm
2. Minor part location changes to ease assembly (DDR3 decoupling caps, LDO resistors, USB crystal caps)
3. Changing the ECP5 input pin for the oscillator to a valid global clock input
4. Removal of ground from the FT2232HQ center pad
5. Update of the USB connector footprint