D3.js force layout graph manipulation

Scope: -Provide a button that will export the d3.js layout graph as png/pdf. Note that d3 force layout graph can include nodes with images. The exported pdf/png should be a copy of the graph and should include the node images as well. - Provide a button that can manipulate the font size/color/bold/unbold format for selected nodes including their links. We should be able first to select multiple nodes on the graph. If no node selected then it will be applicable for all nodes/links. if nodes selected then only the selected nodes and their links will have the format changed.