Port specific settinigs defined in mpconfigport. FreeRTOS and semphr
headers added to define SemaphoreHandle_t for the SYNC_T.

Port specific settings defined in mpconfigport.

- A single ffcon.h file to configure fatfs settings across ports.
- A single diskio.h file with common drive definitions.
- Removed now reduntand ffconf_template.h.

Now, if we build for an architecture which doesn't have dedicated support
for getting registers for GC scanning, fallback to setjmp-based method
automatically. It's still possible to force setjmp-based implementation
on archs with dedicated support (e.g. for testing, or for peculiar calling
conventions/optimizations).

Currently, the only place that clears the bit is in gc_collect.
So if a block with a finalizer is allocated, and subsequently
freed, and then the block is reallocated with no finalizer then
the bit remains set.

This could also be fixed by having gc_alloc clear the bit, but
I'm pretty sure that free is called way less than alloc, so doing
it in free is more efficient.

This patch allows you to stop auto-indent by pressing enter on a second
blank line.  Easier than having to use backspace, and prevents new users
from getting stuck in auto-indent mode.

This patch adds/subtracts a constant from the 30-bit float representation
so that str/qstr representations are favoured: they now have all the high
bits set to zero.  This makes encoding/decoding qstr strings more
efficient (and they are used more often than floats, which are now
slightly less efficient to encode/decode).

Saves about 300 bytes of code space on Thumb 2 arch.

Initial power up also includes VBAT.

If LSE is configured but fails to start, LSI is used until next full power
cycle.  Also handles STM32F7xx variant.

The default setting of using the "highest" method available doesn't
work with some servers like Microsoft Azure. TLSV1 seems to work with
pretty much any server.

This fixes paste mode (Ctrl-E) which was not working for the
telnet REPL.

I left memzip in for the time being, so you can choose in
the Makefile whether to USE_FROZEN or USE_MEMZIP.

It looks like using frozen saves about 2472 bytes (using my
set of 15 python files), mostly due to overheads in the
zip file format.

- use correct 'mingw-w64' package name
- small grammar fixes
- modify Cygwin build instructions to use that same compiler as well: the
  original mingw is stuck at gcc v4.7 and does not seem to be updated anymore
- make it clear thet uPy also builds using Visual Studio versions > 2013

Reported here: http://forum.micropython.org/viewtopic.php?f=2&t=845

Ubuntu's mingw32 has gcc 4.2.1, which is rather old and has incorrect
non-initialized variable analysis which produces warnings, which
per MicroPython default settings get turned into errors.

Contains implementation of ?: (non-capturing groups), ?? (non-greedy ?),
as well as much improved robustness, and edge cases and error handling by
Amir Plivatsky (@ampli).

Otherwise for code like:

while (socket->incoming == NULL) {
    LWIP_DELAY(100);
}

a compiler may cache it in a register and it will be an infinite loop.

py/mphal.h contains declarations for generic mp_hal_XXX functions, such
as stdio and delay/ticks, which ports should provide definitions for.  A
port will also provide mphalport.h with further HAL declarations.