Creates an FCurve parameter definition for use with a CustomProperty
or CustomOperator. An FCurve of this type is often called a "Profile Curve"
because, unlike most FCurves, this curve does not animate any parameter, but instead is available for
use in any fashion the plug-in developer or user wishes.
Unlike parameters that have simple types like an Integer or a String, this Parameter is an instance
of an FCurve. It uses units of Frames for its x axis, but because it does not directly animate any
object this axis can actually be interpreted in any fashion. An example use of an FCurve
parameter can be found on the Bulge Operator.
The FCurve object is retrieved via the Parameter.Value method.
This should not be confused with the method for retrieving an FCurve
that is animating a "basic" parameter (the Parameter.Source method).
In order to view the FCurve on the Property Page for the CustomProperty or
CustomOperator use PPGLayout.AddFCurve.