lang: Add module variables

lang: Check against None, not truthiness

lang: Remove useless abort

lang: Use an object_list for use_modules

lang: Rename module args to use_modules

lang: Pass dependencies to modules

lang: Add module loading dependency walker

lang: Add code to find a module by its name

lang: Add a second module as a test

lang: Parse a module ID to the compiler

lang: Error on compile pass failure

lang: Read module name and module uses

lang: Rename number to rational

lang: Move abort_msg and abort_if to vm

lang: Pass VmState to abort

lang: Couple object functions to VmState ...

This is needed for coupling abort() to VmState and stack traces.

lang: Add jumps (tail calls) ...

This isn't the cleanest implementation but it works.

lang: compile: Fix error handling on invalid command

lang: compile: Fix clauses print

lang: Allow whitespace

lang: Add ElseIf statements

lang: Add else clauses

lang: Only allow creating variables outside conditionals

lang: Add support for multiple if statements

lang: Label conditionals better

lang: Show multiple IR comments

lang: Add JUMP_ALWAYS bytecode

lang: Add simple If statements

lang: compile: Exit cleanly on error

lang: compile: Split bytecode generation in two