We previously completely avoided loopy for temporary declaration.
We now rely on it again, but have DuneTemporaryVariable, which is
capable of doing a bit more things (and at the same time handles
the indexing question)

* Enable backend functions which are *not* generators
* Use the sumfac switch as a default switch

Needs a small fix in loopy (MR opened).

It is a memory reinterpretation

... instead of reimplementing it all over the place

That allows us to load that file as a pandas frame.

They are concepts that are not really necessary with local
storage, that I do not really want to explain to other people.

Only register generators globally. This makes inspection of cache
items much easier.

This reverts commit e1bbce4c.

It allows the sorting of preambles having different
cache item type.

including CallInstructions for accumulation etc.

major remodelling of the DuneTarget