Merge pull request #2959 from RosettaCommons/JackMaguire/MultistageRosettaScripts
Adding Clustering Feature in Multistage Rosetta Scripts
I am adding the ability for Multistage Rosetta Scripts to increase diversity by clustering results between stages. I will talk about this more at winter rosettacon next week if you are interested.
I expect it to look something like this:
```
<PROTOCOLS>
<Stage num_results_to_keep="2000" >
...
</Stage>
<Cluster num_results_to_keep="1000">
<SomeKindOfMetric/>
</Cluster >
<Stage>
...
</Stage>
</PROTOCOLS>
```