Add a “Working” or Rotating circle or whatever while graph is generating

[Zodiase]

There is already a animating progress bar when the graph data is being loaded. The animation, however, will not play (same for everything else on the page) while the graph is being generated/rendered since the main thread of the browser is being occupied. I don't think this is fixable (without a long period of time playing with experimental technology that may not work across all browsers).

[abrin]

at least add a please wait

[kintigh]

From my standpoint the current state is OK.