Add board-io, replace sevenseg in sw

hw/fpga/addr_decode.sv

hw/fpga/board_io.sv

hw/fpga/hvl/cs_testbench.sv

hw/fpga/super6502.sv

sw/board_io.h

sw/board_io.s

sw/io.inc65

sw/irq.c

sw/main.c

sw/tests/test_main.c