[testconstraints] General cleanup

- Use PkLocalFiniteElementMap throughout
- Clean up includes
[testdatahandle] Fight bitrot

- clean up includes
- fix deprecation warnings in YaspGrid constructors
- Switch to QkLocalFiniteElementMap
[Tests] Drag more of our unit tests into the present
[ISTL] Silence compiler warning about comparing different enum types on GCC 4.8