Effect properties should be callable

[timhaywood]

Currently you can only access effect parameters with the .param() syntax. You should be able to call them directly, as you can in Ae:

let highlightLine = thisComp.layer("control").effect("line to hilite")("Slider").value;

[timhaywood]

Looks like we should be able to fix this by adding an interface defintion (as well as the class) to add a call signature to Effect.

interface Effect {
	(effectName: string): Property<any>
}