imagej.legacy: use @Parameter injection
imagej.legacy: add missing javadoc paragraph marks
imagej.ui.swing: use @Parameter injection
OverlayFigureView: fill in missing javadoc
OverlayFigureView: use consistent variable name

It now matches the class name, as well as DatasetFigureView.
Flatten: clean up style
SwingOverlayManager: remove obsolete code
WIP: add FIXME notes to eliminate redundant logic