LOAD_METHOD bug was: emitbc did not correctly calculate the amount of
stack usage for a LOAD_METHOD operation.

small int bug was: int was being used to pass small ints, when it should
have been machine_int_t.

* Add SD card test to fix warning

* Remove include mpconfigport.h from file.c

* Issue #232

On my machine, 'import array' in CPython tries to load the array test.

unix: Initial FFI module implementation

Foreign Function Interface module allows to load native dynamic libraries,
call functions and access variables in them. This makes possible to write
interface modules in pure Python.

This module provides thin wrapper around libffi. ctypes compatibility might
be possible to implement on top of this module (though ctypes allow to call
functions without prototypes, which is not supported by libffi (i.e.
implementation would be inefficient))).

This is special feature for FFI.

Fix implicit double conversion warning

* Add missing LCD definitions for STM32F4DISC target, current code
  breaks build.

Otherwise, some generator statements still may be spuriously executed on
subsequent calls to next()/send().

Implement send() method for generators.

unix Makefile: -Og doesn't work (at least) with gcc 4.6 below.