store and view multiple angles and timepoints in one hdf5 file.
now using UnsignedShortType in ViewRegisteredAngles.
clean up
* split isVisible() into isActive() (whether source is shown in fused mode)
  and isVisible() which is used for the BoxOverlay and describes whether
  the source is actually displayed currently.
* move SpimViewer.SourceAndConverter to new file.
* incorporate recent changes into Multi3DViewer.
add javadoc
experiment with decreasing screenImage resolution to speed up interactive rendering.
use multi-resolution data in the hdf5.
Shared cell-cache based on SoftReferences. adapted from Stephan Saalfelds CATMAIDRandomAccessible.
clean up
timing rendering and hdf5 IO
Rendering screen-images in successively higher resolutions.
Some rendering code was copied from imglib2-ui, because we will require
a tight integration between io, rendering, and timing.
* moved most of the painting logic into SpimViewer.
* basic strategy for switching screenImage resolutions and mipmap levels adaptively.
* some refactoring.
* do not use SourceDisplay directly to paint MultiBoxOverlay. Instead, use a list of IntervalAndTransform.
* synchronize methods that modify SpimViewer state.
* some refactoring
add javadoc
make inner class SpimViewer.SourceDisplay static
rename TMPsetBufferedImage() method, fix comments
remove mipmap slider from gui
per-thread stop watches for Hdf5 loading time
add javadoc
Use minimally modified TransformEventHandler3D that allows to drag the image with the right mouse button (as well as with the middle one).