[IMP-dev] cleanup of cruft

Can we just delete everything in kernel/doc/examples? The code I looked at doesn't work any more. Andrej pointed Marc at IMP and he was, quite reasonably, trying to figure things out based on code there.

In addition, I Ben sets it up so that scons test runs the code in examples, I'll submit a few more reasonable instances. If the code doesn't get run, it will just rot again. Thanks.

Finally, can we delete all the restraint IO stuff from the XML loader? It uses restraints we don't really want people to use, is quite inflexible etc. And I would not want someone to be tempted to use it.