Log warnings when using non-existent options

Fixes #343 

This was fun! Some highlights:

  - I discovered a previously-undocumented option, `gridLinePattern`.
  - I removed a few references to non-existent options from auto_tests.
  - I switched auto_tests to use new-style options where they weren't explicitly testing old-style options.
  - I switched all the tests to use new-style options.
  - I discovered that `isPixelChangingOptionList` didn't know about new-style per-axis and per-series options.

I fixed this last item, but this revealed that there were some pixel-changing options which were marked as not being pixel-changing. This is a bit scary!
Good question. I'd expected to have some false positives for this warning, but I'm struggling to think of any reason that would happen. Let me get back to you on this!