editor.html

[michaelpb]

First task of MDU is supporting better editing for modulojs.org and tutorials etc

• eventually all /demos/ will be replaced with editor.html based one that should have a copy / saveFileAs / etc type feature.

• Eventually, editor.html should be capable of running mgmt commands, and thus making it even less useful (e.g. editor.html could ssg an entire project and offer a tar to download!)