add check for recent-enough npm version by @nathandunn, fixes #828
add check for recent-enough npm version by @nathandunn, fixes #828

GMOD/jbrowse,GMOD/jbrowse,GMOD/jbrowse,nathandunn/jbrowse,GMOD/jbrowse,nathandunn/jbrowse,GMOD/jbrowse,nathandunn/jbrowse,nathandunn/jbrowse,nathandunn/jbrowse