This simplifies the API for objects and reduces code size (by around 400
bytes on Thumb2, and around 2k on x86).  Performance impact was measured
with Pystone score, but change was barely noticeable.

Saves 768 bytes code space on Thumb2 archs.

This has implications all over the place. I have to admit that
you can instantly see that usability improves, but it costs 3K.
At the same time I took the oportunity to rename the '/SFLASH'
drive to '/flash' which improves compatibility with the pyboard.

Fixes msvc linker warnings about mismatching sizes between the mp_obj_fdfile_t
struct defined in file.c and the mp_uint_t declarations found in modsys.c and modbuiltins.c

Also prevents some of the weaker syntax parsers out there treating the whole
'*/*const*/' part as a comment

This patch gets full function argument passing working with native
emitter.  Includes named args, keyword args, default args, var args
and var keyword args.  Fully Python compliant.

It reuses the bytecode mp_setup_code_state function to do all the hard
work.  This function is slightly adjusted to accommodate native calls,
and the native emitter is forced a bit to emit similar prelude and
code-info as bytecode.

Without this patch deleting a property, or class with descriptor, will
call the setter with a NULL value and lead to a crash.

Warnings lead to programming errors - as expected.

splitlines() occurs ~179 times in CPython3 standard library, so was
deemed worthy to implement. The method has subtle semantic differences
from just .split("\n"). It is also defined as working for any end-of-line
combination, but this is currently not implemented - it works only with
LF line-endings (which should be OK for text strings on any platforms,
but not OK for bytes).

Currently supports only x64 and Thumb2 archs.

This implementation is smaller (in code size) than #1024.