[tclquadcode] callframe-impl branch, and progress toward namespace variables.

[Kevin K. <kev...@gm...>]

I've managed to resurrect the kbk-namespace-variables branch, where
I'm continuing to develop toward support of [variable], [namespace
variable] (including [global]), [upvar] and variables with namespace
qualifiers. Nothing in that area is working yet, but I've at least got
it back in sync with callframe-impl and I'm gradually knocking out the
typos.

But that raises another question: At what point is callframe-impl
ready to land into the trunk? It passes all the demos, and all the
demos run as fast or faster in callframe-impl as they do in the trunk.
It's seeming pretty stable, and I'm not planning to do further
development there without further branching (as I'm doing with
kbk-namespace-variables). Are we ready to call the first round of work
on callframes 'complete'?

About the only thing that I see that's obviously still needed is that
the code issuer is still emitting some warnings:

WARNING:stdlib.tcl:3513:tcl.callframe.init not yet finished
WARNING:stdlib.tcl:3541:tcl.callframe.clear not yet finished

I don't know what the significance of those warnings is, otherwise I'd
simply have promoted the code already. We obviously lack a test case
for whatever is missing.

Kevin