2e1764a3bf486929c97f6a7a24a9cab4f0055de4 - fixed weird behavior with checkboxes.

The version upgrade represents the first bit of CodeMirror usage, which is preferable for editor changes at the least. The more CodeMirror-specific code I write, the more complex the extension gets. With any luck, if I implement more advanced features using that API, I'll be able to keep it simple.