update requirements.txt to make it clear that BayesDB depends on crosscat
update requirements.txt to make it clear that BayesDB depends on crosscat

poppingtonic/BayesDB,JDReutt/BayesDB,poppingtonic/BayesDB,poppingtonic/BayesDB,poppingtonic/BayesDB,JDReutt/BayesDB,poppingtonic/BayesDB,JDReutt/BayesDB,JDReutt/BayesDB,JDReutt/BayesDB