Cluster are now AGSGraphics.
Fixed Coverages now that everything's a graphic. Refactored the coverage calculations too.
Fixed cell spacing and multiple zoom level grids.

Now ready to build out the hierarchy code.
Tidy and remove debug output.
Refactored and reworked for hierarchical clustering
hierarchical clustering working better.
Bulk Load + progress reporting.
Reworking for performance. Avoid dictionaries and expensive key copies, avoid creating AGSPoints for grid centroids, propagate features up the cluster hierarchy…
Progress Notification and a few efficiency improvements here and there.
Switch some Dictionaries to Arrays for added performance.
Added logic on Coverage calculation for even better efficiency (+ more cleanup)
Renaming, refactoring, and tidying up.
Consolidate the AGSGraphic category
Major refactoring, renaming, and tidying of public interface.