Census intial checkin
Working...
Added Comparator support to RLE.  Closes #21.
Pointed at new data location.
Merge branch 'Census' of github.com:JosephCottam/AbstractRendering into Census
Modified Census for just image output.
WIP: Region selection on ARPanel.
Draw a box on an ARDisplay.
Removing selection from display.  Headed towards a layered approach.
Renamed 'compound' to a more descritive name.
WIP: Infrastructure changes for enhance button (doesn't work yet).
Rebuild zoom/pan machinery into simpler system.  Closes #29
Subset render under new architecture working (and misc other fixes).
Overlay infrastructure draft complete.  Time to tie-in subset-based specialization.
Improved mask/unmask overlay information.
More work on overlay
Overlay selection region tracks dataspace.
Enhance button works...but you have to toggle it for every change.
Enhance stable under zoom/pan (at the cost of the view-relative transfer flag).
Enhance button stability under zoom...but there is flicker.