PR #435 caused demo titles to regress using file names

[achabotl]

Problem Description #435 exposes all demo files, which is good, but we lost the readable titles that were previously defined in examples/demo/demo.cfg. Now, the file names are the demo titles, and not all of them are useful. We also lost the previous grouping of demos.

Expected behavior:

Maybe rename demos? Maybe recreate the folder structure that was manually defined in demo.cfg.