lang: Switch to mini-gmp rationals for number representation

lang: number: Add Equals

lang: Rename number "Minus" To "Subtract"

lang: number header cleanup

lang: Use a single number_math call with operations as priv

lang: Add private data to vtable calls ...

This will be useful for re-using calls with compile-time data.

lang: Include types.h in object.h

lang: Handle all object allocation in object.c ...

This makes object a purely opaque type now

lang: Remove useless object cleanup checks ...

Once again we assume that we've gotten here correctly based on class data.

lang: Simplify number functions

lang: Set extra variables to NULL after dropping

lang: Always place VmState first in function calls

lang: Remove arg_count and rely on stack depth instead

lang: Add opaque types for Object and VmState

lang: Switch to callee cleanup of non-return arguments ...

This simplifies calling things and will allow proper tail calls.

lang: Add back reference counting ...

The basic idea here is that we transfer ownership to and form the stack,
and clean up references that way.

lang: Remove checks for obj->class_data ...

I have no idea how these could even trigger.

lang: Drop reference counting, embrace leaking ...

I will add proper garbage collection later

lang: Wrap stack functions

number: Don't check if return is NULL ...

This doesn't really matter since we will overwrite it

lang: Replace args with a vm_state stack ...

This doesn't have any functional changes at the moment but will
aid in adding proper stack support in the future.

lang: Add Minus operation for numbers

lang: Fix arg counts to include return value

lang: Pass NULL values to calls first instead of later ...

This looks a bit awful right now but will be important later on
when we add proper support for calls in bytecode.

lang: Put return value as new args ...

This avoids the dispatch having to free values.

lang: Remove unused references to stdio.h

lang: Use static qualifiers for internal functions and data

lang: Return values in args ...

This allows multiple return values which makes things a lot easier.

lang: Implement classes