Some small code clean-ups that result in about 80 bytes ROM saving for
stmhal.

msvc: Use built-in alignof

Multiplication of a tuple, list, str or bytes now yields an empty
sequence (instead of crashing).  Addresses issue #799

Also added ability to mult bytes on LHS by integer.

This also fixes a 'unnamed type definition in parentheses' warning on the
alignof implementation define in binary.c

The only change is line-ending convesion to LF.

Also disable gc module on bare-arm port.

Also fixes compiler error in moductypes when compiled without debugging.

Addresses issue #778.

Can now index ranges with integers and slices, and reverse ranges
(although reversing is not very efficient).

Not sure how useful this stuff is, but gets us closer to having all of
Python's builtins.

reversed function now implemented, and works for tuple, list, str, bytes
and user objects with __len__ and __getitem__.

Renamed mp_builtin_len to mp_obj_len to make it publically available (eg
for reversed).

Saves code bytes and makes it faster, so why not?

Fixes #795.

Thanks to David Siorpaes.

Similar to other methods and following CPython3 strictness.

This happens for example for zero-size arrays. As .get_buffer() method now
has explicit return value, it's enough to distinguish success vs failure
of getting buffer.

Addresses some issues from #585.

Trying to move towards consistency, let's use _ exclusively in names of
source files (eg .c, .h, .csv).