Ensure that we export ${MPI_INCLUDE_PATH} _before_ the
Zoltan_INCLUDE_PATHS

- Otherwise it will lead to nasty segfaults when executing MPI programs.
Various minor MPI fixes.

- New ctor: MPIInitializer(argc, argv)
- Add field logstream to RuntimeMPI
- Some profiling information is written to the logstream in generated
MPI code.
- Removed some unused variable warnings.
Gave a CMake project name to the examples.