Supports suspend and hibernate modes. Waking is possible throug GPIO
and WLAN.
The mpcallback class is generic and can be reused by other classes.

Also add another method to change the pin's interrupt mode
on the fly.

Such functions are never used after MicroPython has started, and they
remain in RAM wasting space. Now they are placed in a special section
named "boot" which sits just before the heap, allowing us to extend
the effective heap area up to the new boot section. Right now, this
gives us back ~1K, but in the future, more functions might end up in
there as well.

Before, both mutexes and semaphores were used. Using only the latter
and with a bit of cleanup to remove some code bloat, we save ~600
bytes of code.

This helps saving ~300 bytes. Thanks to dpgeorge.

The safe boot pin, when pulled high during reset rolls back the
firmware to the "factory" image and skips execution of 'boot.py'
and 'main.py'. This is useful to recover from a crash condition.
The system led is used mostly to signal errors.

Also improve pybsd, and make it save it's pin configuration.
This is a necessary step towards supporting the CC3200 low
power deep sleep (LPDS) mode.

These definitions help on making modwlan.c usable by other ports
with the CC3100.

Also change other methods' names to make them consistent.

Use the simplelink wrappers instead. This is one step further
towards having a single module for the cc3200 and the cc3100.

This commit will not build, it exists just to track changes.

Preparing this to move to drivers/ directory, want to make it as similar
to original code from TI as possible.

This is how it should be, so one knows exactly where the includes are
coming from.

Saves around 1.3K. At the same time re-enable MICROPY_PY_SYS_EXIT
since it doesn't take much space and might be useful for certain
scripts.

Disabling MICROPY_EMIT_INLINE_THUMB gives us back around 6K of
precious RAM.

I2C objects can be freed by the GC and a __del__ method is provided
in order to de-init the peripheral prior to being garbage collected.
UART objects are now added to a local list and this list is now part
of the VM_STATE.