Split inout into in and out for i2c, better for internal use in fpga
Add a couple more zpu out regs
USB support - larger rom/ram support
Added 32-byte write support to ROM area! For MIST external sector buffer. TODO: Smarter method...
Added simple dma for faster sd card reading
Allow SPI clock speed to be set by generic. It was running at half speed for 28MHz platforms vs 58MHz platforms. Need to improve spi speed since byte wise writing is too slow loading roms - 8 seconds on startup!
Cleaned up ZPU into slightly more generic form, though still clearly atari core targetted. Added inital tb, though needs rom to verify more. MIST sector side removed, but should be possible with external changes. Now ZPU instead has lots of GPIO.