Implement visual script disassembler/debugger

[darkf]

Being able to select an object and hit a key to bring up a visual disassembler and/or debugger would be a big help to track down obscure scripting engine bugs.

It could simply be a disassembly window showing the full script disassembly and where the program counter is, what the current LVARs/MVARs/GVARs are, and possibly execution controls (breakpoint, single step, run...)

It could also turn on and show fine-grained logging for that script, e.g. trace all scripting calls made and their arguments / return values.