SharedPreferences: Nit API wrapping android SharedPreferences class

A module wrapping 'android.content.SharedPreferences' allowing to load/save data to internal storage for the android platform. Some tests have been added to the mnit_simple example. 

The compiler has been slightly modified to ignore '\n' in java extern types.

As asked by @privat and @xymus to store persistant game data.
Signed-off-by: Frédéric Vachon <fredvac@gmail.com>
Ca vaudrait le coup de tester les defauts aussi, non?
~~~
assert sp.bool("bad key", true) == true
assert sp.float("bad key", 1.0) == 1.0
# etc.
~~~

Autre question, que se passe-t-il si on utilise un mauvais type ?
genre `print sp.int("a_string", "ZZ")` ?