Leniently handle non-well-formed data and faithfully reproduce it on output

Here's one option for addressing https://www.pivotaltracker.com/story/show/81380614

The current behavior (in `cbeer-rdf-types`, not sure about `master`) is to error on non-well-formed data. This is the other options. The user wants to store it, and we let them.

@ajs6f ?