code cleanup

Remove lots of dead and unused functions.  Improve code formatting.
disasm: add disassembler to debugger

You can now disassemble an arbitrary portion of memory.

Note: the disassembler doesn't understand 0xa5 opcode yet.
debugger: trim code down a little

Reorganize calls so that everything fits better.  Remove some more
unnecessary calls.
ax211: decrease threshold for failed debug mode

We used to wait several seconds for the card to fail to enter debug
mode.  It turns out that we know if it's failed after only a few
seconds.
debugger: add disassembly feature

The code came from
http://home.earthlink.net/~davesullins/software/dis51.html