Update dev-dependencies

Author: wooorm

package.json

@@ -15,13 +15,13 @@
     "index.js"
   ],
   "devDependencies": {
-    "browserify": "^11.0.0",
+    "browserify": "^12.0.0",
     "eslint": "^1.0.0",
     "esmangle": "^1.0.0",
-    "istanbul": "^0.3.0",
+    "istanbul": "^0.4.0",
     "jscs": "^2.0.0",
     "jscs-jsdoc": "^1.0.0",
-    "mdast": "^1.0.0",
+    "mdast": "^2.0.0",
     "mdast-comment-config": "^1.0.0",
     "mdast-github": "^1.0.0",
     "mdast-lint": "^1.0.0",