Convert to Polymer 3

[rediche]

Should be done once Polymer 3 is released. Should be around a few weeks from when this issue is created. This should be able to be automated with Polymer Modulizer.

Down the line components should be rewritten to be made with LitElement rather than PolymerElement. This could result in a rather big rewrite of the project.

Also implement the new material design webcomponents instead of paper-elements.