This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.

There were several different spellings of MicroPython present in comments,
when there should be only one.

In a few places the cc3200 port uses the incorrect spelling Micropython
instead of MicroPython.

The code conventions suggest using header guards, but do not define how
those should look like and instead point to existing files. However, not
all existing files follow the same scheme, sometimes omitting header guards
altogether, sometimes using non-standard names, making it easy to
accidentally pick a "wrong" example.

This commit ensures that all header files of the MicroPython project (that
were not simply copied from somewhere else) follow the same pattern, that
was already present in the majority of files, especially in the py folder.

The rules are as follows.

Naming convention:
* start with the words MICROPY_INCLUDED
* contain the full path to the file
* replace special characters with _

In addition, there are no empty lines before #ifndef, between #ifndef and
one empty line before #endif. #endif is followed by a comment containing
the name of the guard macro.

py/grammar.h cannot use header guards by design, since it has to be
included multiple times in a single C file. Several other files also do not
need header guards as they are only used internally and guaranteed to be
included only once:
* MICROPY_MPHALPORT_H
* mpconfigboard.h
* mpconfigport.h
* mpthreadport.h
* pin_defs_*.h
* qstrdefs*.h

This follows the pattern of how all other headers are now included, and
makes it explicit where the header file comes from.  This patch also
removes -I options from Makefile's that specify the mp-readline/timeutils/
netutils directories, which are no longer needed.

Most of cc3200 uses explicit simplelink calls anyway, and this means there
are no longer any clashes with macros from the C stdlib.

ftp.c is the only user of this function so making it static in that file
allows it to be inlined.  Also, reusing unichar_toupper means we no longer
depend on the C stdlib for toupper, saving about 300 bytes of code space.

vfs.h is for generic VFS declarations, and vfs_fat.h is for VfsFat
specific things.