Various bugfixes, changes to bring in line with current versions of dockers and revisionary
Hack together a Codemirror 4 build process to replace the online compression utility that doesn't quite work.

Monkey patch the Markdown mode to look for $math mode$ specifiers
Patch InlineAttachment to allow it to insert text at position of cursor for CodeMirror
Updated collapsible styles
Fixed breadcrumbs to link to proper listings pages
Updated editor with lots of functionality