Add Lowpass filtering Sensors

[shahmirj]

Low pass filtering will ensure that values are not overly skewed. For more information refer to http://developer.nokia.com/Community/Wiki/How_to_get_pitch_and_roll_from_accelerometer_data_on_Windows_Phone

For example:

alpha = 0.5;
g.x = g.x * alpha + (lastg.x * (1.0 - alpha));
g.y = g.y * alpha + (lastg.y * (1.0 - alpha));
g.z = g.z * alpha + (lastg.z * (1.0 - alpha));

where last.{x,y,z} are values previously recorded