Tune drivetrain.

Add force knob, efficiency, IMU

Change-Id: I4fd12665490d4e535d5890c2edf8ae611938333d
diff --git a/y2014/control_loops/python/drivetrain.py b/y2014/control_loops/python/drivetrain.py
index 77e8254..e8fdb56 100755
--- a/y2014/control_loops/python/drivetrain.py
+++ b/y2014/control_loops/python/drivetrain.py
@@ -20,6 +20,7 @@
                                           q_pos_high = 0.12,
                                           q_vel_low = 1.0,
                                           q_vel_high = 1.0,
+                                          has_imu = False,
                                           dt = 0.005,
                                           controller_poles = [0.7, 0.7])