improved the performance of the filesystem loader
removed the ability to register a global variable after the runtime or the extensions have been initialized
simplified code
simplified code
simplified code
fixed a unit test as Twig_ExistsLoaderInterface has been merged into Twig_LoaderInterface
remove unneeded string cast
remove string casts from loader which was done for template reference objects, but this type of parameter is not contracted by the LoaderInterface
added missing deprecation notices
removed deprecated tests
removed deprecated Node::toXml() method
udpated the docs for 2.0
dropped support for PHP 5.2