make performance enhancements a bit better
make performance enhancements a bit better

KonstantinShemyak/cytoscape.js,soomin-maeng/cytoscape.js,cytoscape/cytoscape.js,rlugojr/cytoscape.js,soomin-maeng/cytoscape.js,KonstantinShemyak/cytoscape.js,rlugojr/cytoscape.js,cytoscape/cytoscape.js