Tabbed navigation feature

The "Tabbed Navigation" feature of Sigma, where screens and applications are accessed via a series of nested tabbed folders, is one of the simplest and most powerful aspects of Sigma, and is explained as follows:

When Sigma starts, it looks in the "Sigma\sigma-web" directory, and lists all the objects in this directory that follow a naming convention of "nnn_Name.sfx", where "nnn" is a three digit integer number (with possibly leading zeros), "Name" is the name of the tab, and ".sfx" is the file suffix, defined below.

Any object in the "sigma-web" folder that follows the above naming convention is represented by a (possibly nested) tab, and is accessible to the browser. Any object in the sigma-web directory that does not follow this naming convention is silently skipped.