Massive refactor

- Use contextual namespaces within Flarum\Core
- Clean up and docblock everything
- Refactor Activity/Notification blueprint stuff
- Refactor Formatter stuff
- Refactor Search stuff
- Upgrade to JSON-API 1.0
- Removed “addedPosts” and “removedPosts” relationships from discussion
API. This was used for adding/removing event posts after renaming a
discussion etc. Instead we should make an additional request to get all
new posts

Todo:
- Fix Extenders and extensions
- Get rid of repository interfaces
- Fix other bugs I’ve inevitably introduced

src/Core/Posts/EventPost.php

@@ -0,0 +1,25 @@
+<?php namespace Flarum\Core\Posts;
+
+abstract class EventPost extends Post
+{
+    /**
+     * Unserialize the content attribute from the database's JSON value.
+     *
+     * @param string $value
+     * @return string
+     */
+    public function getContentAttribute($value)
+    {
+        return json_decode($value, true);
+    }
+
+    /**
+     * Serialize the content attribute to be stored in the database as JSON.
+     *
+     * @param string $value
+     */
+    public function setContentAttribute($value)
+    {
+        $this->attributes['content'] = json_encode($value);
+    }
+}