Feature: Persist drawing in local storage

[bensivo]

initial Implementation is done, but there is some issue.

If you move a hydrated node, as thing you do, suddenly mouse:up events don't fire anymore. This breaks the draw-edge service and panning.

I've nailed it down to the call to update the text-store from within the object:modified event. I believe because this has the downstream effect of re-rendering the canvas, it never finishes the previous event "object:modified", which breaks the event listeners somehow.

[bensivo]

Another issue, the fabric canvas loads before the font does, so the nodes are not drawn in Roboto