Port the preprocessing/meshing folder from the SeisSol repository to here

[davschneller]

This PR copies all programs in the preprocessing/meshing to this repository. Also, gmsh2gambit now supports CMake (scons is still left in for now, but we may remove it freely). The scripts contained in preprocessing/meshing itself are now located in legacy_scripts (if they are needed at all by now).

This PR is a prerequisite for SeisSol/SeisSol#872 to be merged.

[Thomas-Ulrich]

Hi,
What about renaming SeisSol/Meshing to SeisSol/Preprocessing, and SeisSol/Visualization to SeisSol/Postprocessing?

[davschneller]

We could do that, I'd say. If we merge everything into a preprocessing repo, then maybe also include the Geodata repo (https://github.com/SeisSol/Geodata ) somehow?

To throw in some alternatives as well:

• merge pre and postprocessing into one—like a SeisSol utils repository, for which we also could include something like PUMgen etc. as submodules
• Or make a Science (or whatever the most useful name for that is) repository for {pre,post}processing/science and keep meshing and visualization and geodata as they are right now

[krenzland]

merge pre and postprocessing into one—like a SeisSol utils repository

great!

PUMgen etc. as submodules

not so great - submodules are awful and especially in this case IMO not useful