Fix implicit double conversion warning
Add missing LCD driver definitions for STM32F4DISC

* Add missing LCD definitions for STM32F4DISC target, current code
  breaks build.
Add LCD check to stdout_print_strn
py: Add unary op not for NoneType, bool, tuple, list, dict; fix for int.
Merge branch 'master' of github.com:micropython/micropython
Merge pull request #231 from iabdalkader/master

Fix implicit double conversion warning
stm: Remove unneccesary include of mpconfigport (already in mpconfig).
array.array: Allow to create empty arrays.
Don't pre-import array module.
array: CPython prints empty arrays inconsistently (only typecode, no []).
Add basic array.array test.
Factor out quoted string print function for reuse (mp_str_print_quoted()).
bytearray: Print objects properly.
mp_obj_new_bytearray_by_ref(): Allow to create array by reference.

This is special feature for FFI.
unix: Initial implementation of FFI module.

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))).
Add FFI module example.
Merge pull request #235 from pfalcon/modffi

unix: Initial FFI module implementation
unix: Fix compile warnings for ffi module on 64-bit machine.
Rename array test to array1 so it doesn't clash with array module.

On my machine, 'import array' in CPython tries to load the array test.
py: Implement 'not' in compiler, and improve rt_is_true.