AWK script for instructions now recognizes "pseudo-types".

:codeidx -> translates to 'int' prints as '%04d'
:symhash -> translates to 'int' prints as '%s [%d]'
Fixed bugs : I_DUP and and I_DUP_ROLL_3 not working properly.

- Added stack-dump code to single_step() in vm.c to track this.
Added command-line & internal flags for more systematic debugging of VM and parsing.