v0.5.1

• Support low gain for active capacitance measurements.
  • This includes adding a flag for gain setting to active capacitance
    message, breaking messaging compatibility
• Increase HV regulator integrator limit
  • On some boards, this limit prevents the controller from reaching target at
    higher voltages
• Add per-electrode capacitance offset calibration
• Feedback controller uses real capacitance units (pF) instead of count