safer guessGroupFromFilename (can be <sample>_ or <sample>.)
when there is no re match, return None rather than crashing
guessSampleFromFilename is now guessGroupFromFilename
parse also dsids from modeA_WH_notauhad
update to new filelist names
add notauhad samples
signals: the groupname here is a shortened version of the sample name
guessSampleFromFilename makes guessGroupFromFilename obsolete
WhDb* also examine the notauhad files (filelists and xsec)
add histo for notauhad
also loop on histo2lnth, but only plot merged region for histo2l