Silence some 404s from the tests

Add an edit.png so we don't get a 404 every time we load some event tiles

karma.conf.js

@@ -51,8 +51,17 @@ module.exports = function (config) {
         files: [
             testFile,
             gsCss,
+
+            // some images to reduce noise from the tests
+            {pattern: 'test/img/*', watched: false, included: false,
+             served: true, nocache: false},
         ],
 
+        // redirect img links to the karma server
+        proxies: {
+            "/img/": "/base/test/img/",
+        },
+
         // list of files to exclude
         //
         // This doesn't work. It turns out that it's webpack which does the