dc_ram: fix ram type for fpga build.
fpga: implement virtual jtag controller.

This uses the Altera virtual jtag so that we can debug the CPU core.
jtag: import Brian Swetland's JTAG tools.
oldland-jtag: add a JTAG daemon.

This converts the remote debug protocol into transactions to the virtual
JTAG.
Update README.
TODO: add a few more entries.