Fix help message for estimate columns.
Fix help message for estimate columns.

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