Do not use continue stuff. Instead precompute the quantities.

Stage instructions are not the solution.

requires an upstream fix

This removes:
- The now obsolete quadrature_loop_statement.
- Quadrature weights are now a globalarg and we do not create a
temporary anymore.

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)

Needs a small fix in loopy (MR opened).

Get endless temporaries who circularly switch around their base storage.
Any temporary may have different shape or dim_tags, reinterpreting the
data at will.

Various fixes, including diagonal jacobian transformations.