Make a web folder accessible. This assumes listings are provided in html form by requesting links ending in a slash. For example, http://autoplot.org/data/pngwalk/. Links to resources "outside" of the filesystem are not considered part of the filesystem. Again, this assumes listings are HTML content, and I suspect this will be changing (xml+client-side-xslt)...
Create a filesystem from the URI. Note "user@" will be added to the URI if credentials are needed and added automatically.
return true if the regular expression for the file is actually a single file with no wildcards. This is tricky because for years a single period (".") has been left in the name, so that "." matches ".", and really screen.png would match screen_png. To contain this logic, this routine is introduced. Presently it just checks for "screen.png" so that a pngwalk of each screenshot (http://autoplot.org/jnlp/v$x/screen.png) can be made, which is useful when looking for old versions.