[DebugBundle] dump() + better Symfony glue
[DebugBundle] adjust after review
[DebugBundle] add tests for twig and for the bundle
[VarDumper] add Stub objects for cutting cleanly and dumping consts
[HttpKernel] tests for DumpListener
[HttpKernel] add tests for DumpDataCollector
[DebugBundle] enhance dump excerpts
[TwigBridge] add Twig dump() function + tests and fixes
[DebugBundle] Enhance some comments