0.1.6

The version jump is due to a misunderstanding on my part about features and publishing crates. Live and learn!

Notes:

• The documentation on docs.rs is now actually kind of good! More examples TK, but it should be better than it was.
• The asciidocr-tck-adapter bin has been deprecated in favor of just using the json backend
• docx backend is now behind a feature, as is is still pretty in-progress
• Code callouts now work
• Ditto some literals