Add firefox specific configuration

manifest.json

@@ -13,7 +13,12 @@
     "default_popup": "/content/popup.html"
   },
 
+  // chrome
   "options_page": "/content/options.html",
+  // firefox
+  // "options_ui": {
+  //   "page": "content/options.html"
+  // },
 
   "background" : {
     "scripts": [
@@ -26,8 +31,9 @@
       "/background/marked.js",
       "/background/remark.js",
       "/background/background.js"
-    ],
-    "persistent": false
+    ]
+    // chrome
+    , "persistent": false
   },
 
   "web_accessible_resources": [
@@ -67,6 +73,9 @@
   "permissions": [
     "storage",
     "file:///*"
+    // firefox
+    // , "webRequest"
+    // , "webRequestBlocking"
   ],
 
   "optional_permissions": [
@@ -74,4 +83,12 @@
     "http://*/",
     "*://*/"
   ]
+
+  // firefox
+  // , "applications": {
+  //   "gecko": {
+  //     "id": "[email protected]",
+  //     "strict_min_version": "57.0"
+  //   }
+  // }
 }