Coupling Interface for Cosimulations
This adds a coupling interface to exchange data between Nektar++ solvers and other programs at real time.
There are currently two implementations: A simple, file-based one and a full-featured CWIPI-based implementation.
I tried to modify the libraries as little as possible. Besides a few fixes and additions to the communicators (MPI::Allgather) i had to modify the Tester to override the command for the CWIPI test.
The DummySolver is only useful for development/testing, so i am not sure if it makes sense having it in the solver/ subdir and the userguide. However, i couldnt find a better place so i am open for suggestions.