First step in creating a Fortran based Poisson solver.
WIP: Temporary commit.
Adding an example where Catalyst uses a separate MPI_Comm*.
Removing bad Python code from example script.
Fixing some build issues and adding in another Fortran example.

Hopefully final interface for the Fortran example
but still have some bugs sprinkled throughout.
Merge branch 'tutorial_example_Fortran'

Conflicts:
	CMakeLists.txt