Add missing Avatar Interface

lib/public/iavatar.php

+<?php
+/**
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+
+namespace OCP;
+
+/**
+ * This class provides avatar functionality
+ */
+
+interface IAvatar {
+
+	/**
+	 * @brief get the users avatar
+	 * @param $size integer size in px of the avatar, avatars are square, defaults to 64
+	 * @return boolean|\OC_Image containing the avatar or false if there's no image
+	 */
+	function get($size = 64);
+
+	/**
+	 * @brief sets the users avatar
+	 * @param $data mixed imagedata or path to set a new avatar
+	 * @throws Exception if the provided file is not a jpg or png image
+	 * @throws Exception if the provided image is not valid
+	 * @throws \OCP\NotSquareException if the image is not square
+	 * @return void
+	 */
+	function set($data);
+
+	/**
+	 * @brief remove the users avatar
+	 * @return void
+	 */
+	function remove();
+}