More robust expansion calculation.  Look Ma!  No operand!
Oops!  Don't forget nested script substitution!
Back on track.
Tighten up expansion a bit.
Set up to (ab)use INST_EXPAND_STKTOP to debug compiler stack estimates.
Experimental super-stack-estimate checker.
Work in progress auditing the stack usage estimates of the bytecode
compiler routines.  Much of this code is ugly and will never find a
place on the trunk, but the problems it pinpoints will be fixed there.

This is now at the point where the test suite of a --enable-symbols=all
build will usefully panic on those tests where stack estimates are
not correct (or where the auditing code itself is still faulty).
merge trunk
repair error.test
Get a proper merge from the trunk going again.
Repair merge of instruction table
Debug printing for [subst] compiles
Compiled [subst] properly track stack adjustments.
Get stack depth adjustments right for INST_DONE opimized [return] compile.
Progress fixing up the stack management of compiled [dict].
debug reporting fix
merge trunk
merge trunk
merge trunk
Stack estimates corrected for dict.test