Make VM stack grow upwards, and so no reversed args arrays.
Change state layout in VM so the stack starts at state and grows upwards. Locals are at the top end of the state and number downwards. This cleans up a lot of the interface connecting the VM to C: now all functions that take an array of Micro Python objects are in order (ie no longer in reverse). Also clean up C API with keyword arguments (call_n and call_n_kw replaced with single call method that takes keyword arguments). And now make_new takes keyword arguments. emitnative.c has not yet been changed to comply with the new order of stack layout.