Chat updates (#92)

* Send PONG responses to PINGs

* Split out client IDs for viewer counts vs. websocket IDs

* WIP username change event

* Display username changes

* Revert commented out code

* Add support for building from the current branch

* Fix PONG

* Make username changes have a unique ID

* Add a version param to js to cachebust

webroot/js/usercolors.js

@@ -84,5 +84,5 @@ function messageBubbleColorForString(str) {
     g: parseInt(result[2], 16),
     b: parseInt(result[3], 16),
   } : null;
-  return 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ', 0.3)';
+  return 'rgba(' + rgb.r + ',' + rgb.g + ',' + rgb.b + ', 0.4)';
 }