Initial import from Alltube app

Removed dependency on Config and LocaleManager classes
Avoid using generic exceptions

classes/exceptions/PasswordException.php

@@ -0,0 +1,14 @@
+<?php
+
+/**
+ * PasswordException class.
+ */
+
+namespace Alltube\Library\Exception;
+
+/**
+ * Exception thrown when a video requires a password.
+ */
+class PasswordException extends AlltubeLibraryException
+{
+}