Self advantage

[Jecel Mattos Assumpcao Jr]

I had used the Self command interface as my simulator's interface, just as you
suggest. When you call up a new simulation it installs the top level
component in a slot called simRoot*. You can then type expressions such as:

     set: u1 nand out To: h After: 3.
     inv ntran source value.
     run.

This only works as long as you limit yourself to one simulation at a time which
is no big deal since Self is single user for now.

I had hoped the the name inferencer would take care of the output as neatly
as this trick helped with the input, but as simRoot* is an assignable slot
I had to write a printString method for each type of object.

A neat side effect is that I can use the simulator interactively or place 
the commands in a file and _RunScript it in.