Fast support measures

[stamatak]

There now is an entire zoo with fast support measures, e.g., aLRT test and derivatives thereof, ultrafast bootstrap (probably not applicable due to the nature of the search algorithm), quartet-based measures: We need to decide at some point which ones we want to integrate.

[amkozlov]

Also look at the "transfer distance": https://www.biorxiv.org/content/early/2017/06/23/154542

Implementation: https://github.com/evolbioinfo/booster

RAxML rapid bootstrapping: https://academic.oup.com/sysbio/article/57/5/758/1618491