lang: Switch to mini-gmp rationals for number representation

lang: vm: Check stack malloc failure

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: Add looping test

lang: number: Add Equals

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

lang: compile: Use -1 for temporary IR locations

lang: boolean: Style fix

clang-format: Fix AlignTrailingComments

lang: Add AST statements and commands

lang: Fix none comparison

lang: Note variable positions properly in IR

lang: Fix OP_END trailer

lang: Rename number "Minus" To "Subtract"

lang: Rename boolean "Not" to "Invert"

lang: Use object_none() instead of NULL

lang: Import boolean code (oops!)

lang: Add None objects to the language