add support for cy.js instance inside postion:fixed div or parent
add support for cy.js instance inside postion:fixed div or parent

closes #256 for factoid

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