Flickering clusters

[lpetka]

I wrote a method that preserves same cluster key across region changes, i.e. SuperCluster engine computes clusters every time region changes and rerenders all clusters even though some of them did not change at all (same coordinates, same point count). Rerendering is triggered by generating new cluster_id which is then passed to cluster component key.

[39otrebla]

@lpetka thanks, this is a good point. Tough we need to make sure the changes are scalable enough to support a huge number of clusters (like it the module supports today).