* a single bashrc / cshrc file for CFDEMcoupling, similar to OpenFOAM
* user-editable section on top, for:
- setting the versions of OpenFOAM and CFDEMcoupling
- setting installation paths
- setting user directory path
* allows to set/unset values from command-line parameters (important for
test harness installation)
* removed unused and deprecated environment variables