Replace kcfinder with elfinder image browser

- KCFinder is GPL, which is incompatible with Apereo
- elFinder is BSD
- elFinder works better on tablets
Make sure all xenith dialog html files are exported
Merge remote-tracking branch 'origin/editor' into develop
Fix inability to save changes with new editor

- Add ?t=time() when retrieving xml data
- Save preview.xml when publishing
- Add explicit save button to save preview
Optimzed ckeditor didn't use nes codemirror plugin

- Fix codemirror blur by rebuilding ckeditor configuration
Don't crop thums in file browser
Add all images used by jquery-ui.css
Merge remote-tracking branch 'origin/editor' into develop
Make sure preview window is large enough