New/updated mouse handlers

yet another hack to make sure the disclosure triangle is properly clickable even though it's inset due to text indent

Overload the less-than operator "<" to implement version comparison

Components that belong to overlay are screened out by the caller (inspector)

draws a distance line when component is selected, showing distance to parent or hovered element

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================================================================== 4. Redesigned paint method ========================================================

must override to set the disclosure triangle color

Call this on every sample in processBlock. Returns a bipolar [-1, 1] signal.

Creates an LfoData object from an XmlElement.