Not yet implemented:

- Vectorization of quadrature loop
- Anisotropic amount of quadrature points per direction

Rename the function and remove the backend switch. Reasoning:

- This function was only called once without the backend switching
  mechanism.
- The function takes different arguments than the pdelab
  pymbolic_quadrature_position.
- It returns only one component of the quadrature point.

They are only to a lesser extent important for our HPC applications
and the vectorization algorithm struggles with the complexity of the
search space.

Avoid explicit doubles.

Avoid explicit doubles.

They are not used in a senseful way anyway and loopy
stumbled over them.

This is currently only used for level 4 instrumentation,
as these start and stop markers were messing heavily with
dependencies in the sum factorization code. This way, the necessary but
ugly work of adding instrumentation is separated much more
nicely.

I was tired of the amount of ifs that changed behaviour
depending on stage 1 or 3. This is a cleaner approach.

It is not necessary anymore

It is applied to the function call...

It would be hard to implement on top of the latest feature and contradict
features projected for the near future.