Initial import from Alltube app

Removed dependency on Config and LocaleManager classes
Avoid using generic exceptions

classes/exceptions/AlltubeLibraryException.php

@@ -0,0 +1,13 @@
+<?php
+
+namespace Alltube\Library\Exception;
+
+use Exception;
+
+/**
+ * Base class for Alltube exceptions.
+ */
+abstract class AlltubeLibraryException extends Exception
+{
+
+}