Phase Dispersion Minimization

	?      list options
	h      graph data
	i,k    graph theta (abscissa) verses frequency or period respectively
	p      graph phase curve for period/frequency at cursor x position (th)
	d,u    delete or undelete respectively the point nearest cursor  (d,ph)
        f      call ICFIT on displayed data                 (data or phase plot)
        j      subtract fit from data, use residuals
	s      set sample range for calculations            (data plot)
	t      reset range to entire dataset                (data plot)
	g      significance of theta at cursor x position   (theta plot)
	a      amplitude and epoch at cursor x position or of plot (th,ph)
	,      set minp or minf to cursor x position        (theta plot)
	.      set maxp or maxf to cursor x position        (theta plot)
	m      mark range and find minimum in this range    (theta plot)
	e      turn on/off error bars on phase plot, and if (phaseplot), replot
	r      replot
	x      remove a trend from the data by removing a bestfit line
	z      flip the y-axis scale
        q      quit

	The following commands may be abbreviated.  If entered without an
	argument; :minp, :maxp, :minf, :maxf, and :ntheta will display the
	named parameter; :show, :vshow will print to STDOUT; :signif, :ampep,
	and :phase, will do the calculation at the remembered period.

	:show [file]		show parameter settings
	:vshow [file]		show verbose information

	:minp :maxp [period]	set/show min/max search period
	:minf :maxf [frequency]	set/show min/max search frequency
	:ntheta [number]	set/show number of points for theta
	:sample [value]		set/show the sample ranges

	:signif [period]	find theta significance
	:ampep [period]		amplitude and epoch
	:phase [period]		graph phase curve

	:unreject		unreject all the data points
	:alldata		reset range to entire dataset
	:origdata		reset data to original dataset