Introduce different methods for realize_input/output
realize_direct_input/output and setup_input/output. The setup methods cover
code generation outside the sumfact kernel function (creating input array or
accumulating result). realize and realize_direct handle the input/output in the
nonfastdg and fastdg code branch.

Seperate interface methods make it a lot easier to find out where each of those
methods will be applied. Besides that most interface classes need to provide
more that two of those methods anyway...

Non-fastdg: Permutation of the input happens before the sum factorization
kernel when we setup the input. This is done by a method of the corresponding
interface class.

Fastdg: In this case the input will always be ordered according to x,y,... This
means the permutation needs to happen in the sumfact kernel. Since we want to
vectorize sumfact kernels with different input permutation in an upper/lower
way we need to do this permutation in the corresponding interface class. This
is done in the realize_direct method and in the vectorized case the
corresponding methods of the scalar sumfact kernels are called.

Note: They are not yet used but in the long term the permutation should be
handled here since it is about input/output setup.

Calculate the evaluation and jacobians of geometry mappings of cells
using sum factorization. By avoiding all geometry mapping of intersections
we can avoid the face-twist problem and just make the grid consistens (not
yet done).

TODO:
- Make grid consistent
- Vectorization
- 3D

Avoid explicit doubles.

Avoid explicit doubles.

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.