Make travis use a more recent node
Make travis use a more recent node

From http://entulho.fiatjaf.alhur.es/guias/how-to-use-node-along-with-other-language-on-travis-ci/

SylvainCorlay/bqplot,SylvainCorlay/bqplot,ChakriCherukuri/bqplot,dmadeka/bqplot,ChakriCherukuri/bqplot,bloomberg/bqplot,bloomberg/bqplot,dmadeka/bqplot,ssunkara1/bqplot,bloomberg/bqplot,SylvainCorlay/bqplot,ssunkara1/bqplot,ChakriCherukuri/bqplot