Better support for testing visualizations in browsers

[AlexLandau]

Right now it's very difficult to test visualizations in a way that reflects how they will work as rendered in browsers on Tiltyard. We should at least have a way that the game server can render game states so they are seen in a browser, and possibly move to that as the preferred/only approach. This would likely involve offering a link to a web page that either is served by a Java servlet in the game server process, or is a file: link to generated static HTML pages in a folder. (I've seen issues with same-origin policies in Chrome with the latter approach.)

This might be combined with a move to JavaScript-based visualizations.