Replace examples with those from the second edition of the AMUSE book

[rieder]

Existing examples are outdated, in some cases not working and often duplicated by others.
This replaces all examples from the "textbook", "syllabus" and "simple" directories with the complete set from the textbook (second edition).

[rieder]

To be done:

• Some tests may use some of the old examples, so these need to be updated
• Add installable package for the examples (they should be installable as "amuse-examples" via pip, at the least - living in the amuse.examples namespace, as this is how they are used in the book).
• a file "AMUSE_updates.pdf" needs to be added, as a file containing any errata for the book.
• missing / later conceived examples may be added later

[rieder]

If we do want to keep (some of) the old examples around, they should be in some directory that makes it clear that these are archived, and not updated. If they are still useful, they should be moved to the new structure.

[LourensVeen]

I don't see how the tests would depend on the examples, but I'll go and do a local build and run them all to check.

I think pip packages, the PDF, and more examples should be separate Issues, so if it doesn't break the tests then I'll merge this, even if it isn't perfect I doubt it'll make things worse.