Updates linux icons for copay

package.json

@@ -12,6 +12,8 @@
   ],
   "main": "public/index.html",
   "window": {
+    "title": "Copay - A multisignature wallet",
+    "icon": "./public/img/icons/icon-256.png",
     "toolbar": false,
     "show": true,
     "visible": true,
@@ -48,8 +50,6 @@
     "grunt-contrib-uglify": "^0.8.0",
     "grunt-contrib-watch": "^0.5.3",
     "grunt-exec": "^0.4.6",
-    "grunt-markdown": "^0.5.0",
-    "grunt-release": "^0.7.0",
     "shelljs": "^0.3.0"
   },
   "scripts": {