Fix nasty little sign of torque and current bug.
Add encoder.steer_rate to lower subplot of plot_estimate().
Merge remote-tracking branch 'oliverlee/fullorderobs' into full_order_observer
Record motor torque instead of motor current.
Initial conversion from greek names phi and delta to lean and steer.
Merge remote-tracking branch 'hazelnusse/full_order_observer' into fullorderobs
Fix field names in plots.

Change field names from phi/delta(dot) to lean/steer(rate) and motor
current to motor torque.