Log Message:
This package includes backported versions of types that were added to
transformers in transformers 0.3 for users who need strict transformers 0.2
compatibility to run on old versions of the platform, but also need those
types.

Those users should be able to just depend on transformers >= 0.2 and
transformers-compat.

Note: missing methods are not supplied but this at least permits the types
to be used.