Replaced buggy simplefold() with a call to simplified call to fold()
Merge branch 'master' of github.com:scottransom/presto
Added DOF_corr() to fix chi2 and made numtrials an option for estimate_offsignal_redchi2
Changed rms_correction() to use DOF_corr instead
Added chi2 DOF correction stuff
Merged prepfold folding and chi2 scaling changes from master