Cleanup of readers

[HomesGH]

ASCII reader

The method readPhaseSpaceHeader of the ASCII reader is not used in the code anymore. Instead, the data of the config xml was already employed to set according values.

It seems that the method readPhaseSpaceHeader of the ASCII reader is just used for tests, see here.

MPI_IOCheckpointWriter and MPI_IOReader

@cniethammer @FG-TUM
Do you know if the MPI_IOCheckpointWriter and MPI_IOReader classes are in use or working at all?

I couldn't find any reference and usage of those in the present code base.

On the history of the MPI_IOCheckpointWriter :

• The class was introduced with this commit 4d3fa08 but didn' work correctly
• According to this commit, it was fixed.

[FG-TUM]

After grepping the whole project, it seems MPI_IOCheckpointWriter is not used at all, and MPI_IOReader is only referenced from commented-out code once in PressureGradient, so it is also unused. Both are not registered as plugins, hence, they will probably not work at the moment.

I'd be in favor of removing them!