Modifications:

- Qk-DG basis instead of Pk-DG
- No blocking
- Lexicographic DOF ordering
- Turning on nonlinear term (Navier Stokes instead of Stokes)
- Add methods for printing residual/jacobi matrix

Note: With the nonlinear term activated the solution of the program
is of course garbage since it does not use a nonlinear solver. Only
residual evaluation and assembly of the jacobi matrix are useful and
can be compared to generated code.

Remove interactive mode

See merge request dominic/dune-perftool!211

It's completely unmaintained andI doubt that it will
at some point what it was intended for...

Feature/fixes for hyperbolic stuff

See merge request dominic/dune-perftool!210

There is way more reasons to interpolate a function into the
solution vector and we cover them with one code path:
* Dirichlet boundary conditions (strong ones)
* Initial conditions for instationary expressions
* Initial guesses for Newton solvers

The visitor state regarding indices needs to be correctly reset
for child iteration in these cases.

These might sound completely silly, but they are useful when writing
code generic w.r.t. the number of components

Divide through h_e for in Stokes application

See merge request dominic/dune-perftool!209

Single Precision support

See merge request dominic/dune-perftool!208

Vectorization with a cost model

See merge request dominic/dune-perftool!189

It has single precision support...

Feature/cache with stackframe

See merge request dominic/dune-perftool!207