Draw section panes (content too?) with WebGL

[jiku]

Would allow great effects, i.e. animations, transitions, and so on. Especially if combinable with THREE particles. Would also help with #79.

HTML-GL

PixelsCommander/HTML-GL#56

For HTML-GL issues (after trying to use it): Freezes on scroll with UIWebView on iOS (9.1)

(Not sure it's worth looking into, since it'll probably go away with Chrome and Cordova abandoning UIWebView.) The displacement demo freezes on vertical scroll in Chrome (46) on iOS 9.1. Presumably because it uses UI- instead of WKWebView, so it's probably affecting Cordova too. I'm working around something like this in an app where a few WebGL canvases still draw on scroll for UIWebView, using iScroll. For Cordova I'm using the Telerik WKWebView plug-in, which might work for this too.