added code mirror widget
added code mirror to the html
added code mirror static media.
no need to declare it as a variable.
be nice to requirements.pip
updating editor via javascript.
dont forget the js.
Merge changes from develop.
Fix PEP8 warnings.
Fix referenced to undefined variable in JsboxAppConfigForm.to_metadata.
Remove codemirror source.
CodeMirror widget implementation.
Use new CodeMirrorTextarea widget.
Remove dependence on django-codemirror-widget and include our own.
Initial codemirror-compressed.js.
Remove old possibly_load_from_url tests.
Hook up new code-mirror CSS and JS properly.
Remove some empty lines.
Use custom SourceUrl widget and sort of connect it up to a code widget.
Make source updating from URL work.