add some more timing data, different (slower) way of finding nearest color, different (slower) way of finding nearest blank spot to fill, add average color fetching
add generic "finder" class
more finder changes
use Finder in Colorset

(after trying kdtrees and finding them to fail because we cannot remove from them, and the vast majority of queries in them return something that is not actually still in the set of remaining colors)
add kdtree back in, but select like 80+ closeset elements from it each time rather than just one
remove old code
just store set of pixels that are blanka and adjacent to a colored pixel to make things faster