mnit_android: adding android_sensors module

Signed-off-by: Romain Chanoir <chanoir.romain@courrier.uqam.ca>
mnit_android/android_app: adding sensor support in android_app

Signed-off-by: Romain Chanoir <chanoir.romain@courrier.uqam.ca>
examples: Adding App mnit_ballz, using android_sensors

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

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

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