Rename PartiaExtractor to PartialExtractor
Rename PartialExtractor to PartialAnalyser for consistency
Rename PerceptualBrightness to BrightnessAnalyser for consistency
Change BrightnessAnalyser.brightness to use a VU meter widget
Add symbolic links to extra/extra/* in Module creator host/ so that the expr etc get picked up since [declare -stdpath] doesn't seem to work.
Fix bug in BrightnessAnalyser where global variable was causing all instances to share the same value for brightness!