Compatibility with base >= 4.7.0.0; bumped version.

Hi there!  I wanted to use your lib as it did exactly what I needed.  I had to fix a small issue with `base >= 4.7.0.0`.

BTW.  Please consider to provide a small test suite and add it to [Stackage](http://stackage.org), because Stackage is awesome.  I would even like to help with that.