add drive stage to slowram_data to improve timing.
fix previous commit
fix sense of slowram_we for slowram_data_drive
disable sprites on startup. remove sending ethernet frame on startup.
work towards buffering slowram_data to improve timing.
add xilinx coregen generated multiplier ready for enhanced sprites.
begin work on enhanced sprites.
work on fastio interface for enhanced sprites.
implement 2x2 transform matrix pipeline.
add sprite_iv.vhdl to simulation target and work on simulation errors.
revert slowram data drive.
add more iomap documentation.
fix typo.
remove $D500x registers from framepacker.
update memory map allocations.