uses three.js to display a stl or obj file. based on http://lazarsoft.info/objstl/
returns a function you can use to create a viewer instance
returns a new viewer and appends the empty canvas to the dom inside containerElement. containerElement has to be a valid dom element, otherwise it will use document.body.
renders the stl to the viewer. calling this again will remove the old model and display the new one
renders the obj to the viewer. calling this again will remove the old model and display the new one
BSD