[WIP] Notifications (#599)

Adds a new notifications feature to the Admin plugin. It will now lookup notifications which are set up on getgrav.org and will inform users, and also alert for new updates and provide awareness on various topics.

Also fixes issue with Array field in `value_only` mode, improperly displaying the key when novalue was set, and fixes issue with drag handlers in Array not showing/hiding properly (#950)

Updated FontAwesome to 4.6.3

vendor/autoload.php

@@ -0,0 +1,7 @@
+<?php
+
+// autoload.php @generated by Composer
+
+require_once __DIR__ . '/composer' . '/autoload_real.php';
+
+return ComposerAutoloaderInitef6e9937a63bd796f32542b02941ee0e::getLoader();