v1.6.1

ControlSystems v1.6.1

Diff since v1.6.0

Closed issues:

• Docstrings for Bode and Nyquist plot functions specify incorrect indexing (#797)
• marginplot + setPlotScale("dB") = no magnitude plot (#798)

Merged pull requests:

• fix pid with Ts keyword (#755) (@baggepinnen)
• Use yscale --> _PlotScaleFunc in some plot recipes (#799) (@baggepinnen)
• warn more against high-order transfer functions (#800) (@baggepinnen)
• handle Infinite delay margins (#801) (@baggepinnen)
• plot the phase guide at the correct phase (#802) (@baggepinnen)
• add stepinfo (#803) (@baggepinnen)
• relax some conversion signatures (#805) (@baggepinnen)