mnit_android: Adding android_sensor module

Signed-off-by: Romain Chanoir <chanoir.romain@courrier.uqam.ca>
mnit_android: changes android_app to support android_sensor

Signed-off-by: Romain Chanoir <chanoir.romain@courrier.uqam.ca>
examples: Adding mnit_ballz, a game using android_sensor API

Signed-off-by: Romain Chanoir <chanoir.romain@courrier.uqam.ca>