hpbox: Sandbox for hp-adaptive methods

This program is used as a benchmark to demonstrate the benefits of parallelization, hp-adaptive methods and matrix-free methods combined.

Initial release.

In the current state of the software, you can solve Poisson and Stokes problems on selected geometries. Algebraic multigrid methods are available for both problem types, while geometric multigrid is only available for the Poisson one. The provided parameter files cover all scenarios that can be solved with this tool.

The release also comes with all parameter files that were used for data generation of the publication mentioned in the README file.