Changed the procedure test to pipe two programs together.

This should help me figure out how to make sure things are closed properly
inside the VM.
Solved the simple case of test-proc failing.
Refactored out more of the VM types into a separate module.
Removed a few (possibly) unnecessary instructions.

(And removed some error output calls which I plan to put back in later).
Made the VM main() create the initial context for the proc module.
Added an indentation target to the Makefile and ran it.
Removed much of the VM code and documentation.

I plan on mostly rewriting it from scratch with a better instruction set,
after adding a few more features to the interpreter.
Added support for lexical assignment.
Did some renaming - `type.h` no longer describes just one type.