fix ambiguous if/else statement
Fix the issue reported by Ian where an MPI implementation does not offer MPI_C_BOOL.
fix some TODOs
fix pressure normalization
add test
Merge pull request #105 from tjhei/fix_a_couple_of_todos

Fix a couple of TODOs
Merge pull request #107 from bangerth/fix-MPI_C_BOOL-issue

Fix the issue reported by Ian where an MPI implementation does not offer...