Merge pull request #34 from mlosch/master

Use hysteresis in motor controller. Use odometry for turning. Recalibrated motor controller. Add motor constant calibrator node.
Merge pull request #37 from mlosch/master

Removed hysteresis. Added pwm spiking. Calibrated pid. I-Term included again
Merge pull request #38 from mlosch/master

Invert turning logic so that it fits to inverted encoder readings