1.0.16 New beta bed view and preheat options

Adds new preheat options (you can disable nozzle/bed preheating from the profile).

Adds a new view style, just like the realistic bed view, but intended to be more compatible. The original bed view was dependent on octoprint css and custom themes and css would easily throw it off. This uses a HTML5 canvas and css/themes should never interfere with the view. Once I'm sure this is ready to go, the beta bed view is going to completely replace the old bed view.