Added tag 0.1.2 for changeset 875f57a264b0

Version bump

Add type annotations to public facing API

The PEP561 marker lets dependent projects using mypy type check code using this
module.

Added tag 0.1.1 for changeset 8f08bd9d2a62

Version bump

Added tag 0.1.0 for changeset 64f694b06df5

Return None when trying to get missing sub-directive

This aligns with the behaviour of get on the top-level directive, previously it
would instead raise an exception.

Initial commit