Easier Packing.

Packing doesn't need grammars to be labeled any more.

Also update Thrax module to 2144de5828e02b064e9e39eec686d36b87440996 (my compact branch) for:
- Packing-friendly output (makes sorting grammar before packing unnecessary)
- Packed-grammar-aware CreateGlueGrammar tool

Pipeline has been changed to reflect these changes.