Small refactorings (similar to pappz' implementation)
Moved preferences to separate package
Add disable function to IController

It is important for the gyro controllers because without this
patch always running the measuring in the background.
Test the available sensors in the preferences
Inline implementation of the SensorEventListener
Add accelerometer sensor
Add overshoot filter and rewrite sensor calculation

- In getRoll and getPitch in GyroscopeController add an overshoot
calculation. It split the overshooted sensor values.

- Rewrite the ratio of the accelerometer sensor's value
Add normalization to the accelerometer
Fix the stucked flightdata on UI after disable
Merge branch 'pull_accelerometer_clean' of
https://github.com/pappz/crazyflie-android-client into
pappz-pull_accelerometer_clean

Conflicts:
	src/se/bitcraze/crazyfliecontrol/controller/GyroscopeController.java

Fixed copy and paste error in TouchController, reset gyro preference if
no sensors are found
Merge branch 'pappz-pull_accelerometer_clean' into bitcraze_master