add check in setup.sh for node >= 6 and npm >= 4, fixes #1026
add check in setup.sh for node >= 6 and npm >= 4, fixes #1026

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