Add the browser field in package.json as a hint to bundlers

The `browser` field in `package.json` will tell JavaScript
bundlers like browserify and webpack to package, replace, or
ignore specified modules for the client-side.

https://github.com/defunctzombie/package-browser-field-spec

Author: remarkablemark

package.json

@@ -27,5 +27,9 @@
   "peerDependencies": {
     "react": "^0.13 || ^15.0"
   },
+  "browser": {
+    "htmlparser2/lib/Parser": false,
+    "domhandler": false
+  },
   "license": "MIT"
 }