This completes instruction support for the Blink tn45 example.

Take argspec pairs directly as an argument instead of taking a
pointer to an argspec pair.

The instruction table is now beefier and has redundant data, but
this simplifies processing. This should simplify upcoming work.

Also, add a "real world" example in AVRA tests, a blink program on
a ATtiny45. Some instructions are commented out because they aren't
implemented yet, but not many.

The output of the program has been verified against AVRA's own
output.

This costs us a bit of space for now but should make things a lot
simpler down the road, especially with "alias ops" which are simple
syntactic sugar for another op.

I had written this when trying different approaches to adding BR and
I forgot to remove it.

Use IX directly for argspec rows instead of going through DE. It saves a bit
of processing. The code was this way because I initially didn't use IX at all,
so as code evolved, that DE translation stayed as an artifact.

It wasn't used much so I inlined it.

It wasn't used much, so I replaced its use in the kernel with direct code
and moved the routine in apps/ed, the only other place where it was used.

ref #80

fixes #80

Also made Makefile actually portable.

markdown formatting was broken. Also, don't mark it as WIP.

This shaves off quite a few bytes from the binary.

This is becoming the new shell, it has to step up to its new responsibilities!

Shell replacement sequence beginning in 3, 2, 1...

Mechanism for assigning inputs to the specified variable is clumsy and uses
binary space. Always using A is much simpler and doesn't seem very limiting to
me. I do that because there's many more "input" commands I'd like to add.

Also, add the new `bshell` emulated tool. BASIC is on its way to replace the
shell.