added a way to designate "veiled" artifacts (with a _ prefix) which are "hidden" in that they do not show up in navigation. made veiling apply only to a single directory level as well as removed the veil prefix. This is useful to make a single page or directory not appear in the menu, but there is still a need to make an entire tree as effectively veiled as well as prevent pages from being generated.
Create a way to designate files and directories as "assets", by default with a $ prefix (which is entirely appropriate because "assets" often refer to things of monetary value). Assets are not considered "veiled", but they will also not be included in generated navigation lists. By default the $ prefix will be removed during mummification. Otherwise there are two important distinctions:
Designating an artifact such as a directory as an asset will apply to all descendant artifacts as well.
In an asset directory tree no pages will be generated. That is, all artifacts that have a PageMummifier will instead be copied over as if they had an OpaqueMummifier. And empty directories will not have phantom index pages generated.
For example, a typical assets tree will look like this:
After mummification with the default configuration this will appear as one would have expected to begin with: