Version bump 3.1.0

* fix openContactForm behavior, it now returns the contact. Also fix
thumbnail saves.
* add openExistingContact, launches native contact app with the
selected contact
* add writePhotoToPath, on android saves thumbnail to given path

package.json

@@ -4,7 +4,7 @@
     "type": "git",
     "url": "https://github.com/rt2zz/react-native-contacts.git"
   },
-  "version": "3.0.2",
+  "version": "3.1.0",
   "description": "React Native Contacts (android & ios)",
   "nativePackage": true,
   "keywords": [