Remove clusters that are reachable to each other

[DJDuque]

Test if the above gives better results. Just by looking through some events, there are some obvious clusters that should not be identifies. It looks like a good chunk of these can be removed with this method e.g. a straight line cosmic, or low energy particles that circle back through the gas.

[DJDuque]

Possible things to try:

• Remove both clusters.
• Keep the "better" cluster (by some metric).
• Merge both clusters into one.