added new icon sizes

manifest.json

@@ -2,15 +2,9 @@
   "name": "Placid Tab 2",
   "short_name": "Placid Tab 2",
   "version": "1.0.0",
-  "manifest_version": 2,
+  "manifest_version": 1,
   "description": "A minimal New Tab page",
   "author": "Kyle Mitchell",
-  "applications": {
-    "gecko": {
-      "id": "placidtab2@kylemitchell.me",
-      "strict_min_version": "57.0"
-    }
-  },
   "chrome_url_overrides" : {
     "newtab": "home.html"
   },