Reliable destruction

[Pierre-Eric.Melchy at uni-konstanz.de]

Hello,

your idea sounds good and handles the exception on teardown as well.
(I did not think about the if XXX!=None check in teardown())
I will now provide each of the instruments with an explicit shutdown()
method which frees the interface card as well.

These methods will be called in a finally clause after run.
I  think this is much better than to wait  for or rely on garbage
collection.

Of course there is a hardware protection of the setup as well.

I am amazed how well Python handles lab instrumentation, it is really
fun to develop with  Py.


Many thanks for your help