Site freeze

To be able to review site source code changes a "Site freeze" option could be added to the Sidebar: When it's enabled, the current site's html, js, and css files are copied in a separate directory (data/siteaddress-freezed) and if the user's browser is request the files then it would be served from this directory until the user disable the freeze feature.

The data files are not affected by this feature and the user still receive/distribute the latest files of the site's source code.