add basic smb notify support

at the moment this only works when using the smbclient based backend

src/IShare.php

@@ -8,6 +8,17 @@
 namespace Icewind\SMB;
 
 interface IShare {
+	// https://msdn.microsoft.com/en-us/library/dn392331.aspx
+	const NOTIFY_ADDED = 1;
+	const NOTIFY_REMOVED = 2;
+	const NOTIFY_MODIFIED = 3;
+	const NOTIFY_RENAMED_OLD = 4;
+	const NOTIFY_RENAMED_NEW = 5;
+	const NOTIFY_ADDED_STREAM = 6;
+	const NOTIFY_REMOVED_STREAM = 7;
+	const NOTIFY_MODIFIED_STREAM = 8;
+	const NOTIFY_REMOVED_BY_DELETE = 9;
+
 	/**
 	 * Get the name of the share
 	 *
@@ -131,4 +142,11 @@ interface IShare {
 	 * @return mixed
 	 */
 	public function setMode($path, $mode);
+
+	/**
+	 * @param string $path
+	 * @param callable $callback callable which will be called for each received change
+	 * @return mixed
+	 */
+	public function notify($path, callable $callback);
 }