Use my marked-ast library from parsing Markdown.
Use CodeMirror's clearOnEnter for marks, instead of custom logic.
Factor out the ellipsis markers into a separate plugin.
Allow widget declarations to include arbitrary user data.
Record a widget's type, not just a unique ID for the type.
Remove CodeMirror-related code from Moonchild core module.
Re-organize the editor into a more self-contained object.
Support editing in Markdown comment blocks.
Add plugin which implements scrubbable numbers.
Add merge diagram from CLR book.
Add more details to README.