* changed cluster colors: they are now generated from HSV values, with H linearly spaced between 0 and 1, and S=V=1. Too similar colors were manually removed.
* updated the keyboard bindings in the ClusterView: now the native bindings are active, except those that involve keyboard modifiers, so as to prevent conflicts with the FeatureView, which has bindings with CTRL+arrows to navigate through the projections.