Categorized examples

That's importing the example file changes from pull request #742 so it's easier to prepare them for inclusion.

* Rebased against current master as the original pull request did cause some conflicts with the latest changes in master)
* Due to file name conflicts, I had to add a second folder for the dumptest output. All the example files are now having the expected files in the dumptest-examples subfolder.
* All example files have ```echo(version=version());``` at the beginning as suggested on the mailing list (@MichaelAtOz)