Add BOOST.fusion as apparently we need that in boost/math/special_functions/erf.hpp.
Add a test to avoid this problem from happening again in the future.
Circumvent a bug in Trilinos 11.10

If we avoid calling GlobalAssemble when copying from an Epetra_FECrsMatrix that uses a
non-local matrix (enabled for Trilinos 11.9 and greater), we do not run into some bad
code in Trilinos causing a segfault. At this point of the code, it is enough if we only
call FillComplete because there should be no communication after all.
Merge pull request #182 from kronbichler/master

Circumvent a bug in Trilinos 11.10
Merge pull request #181 from bangerth/add-fusion-to-boost

Add fusion to boost
MPI_Allreduce is apparently unable to accept input and output arguments at the same location.

Fix this by determining when &input=&output and in that case pass MPI_IN_PLACE.
Add a bunch of missing tests for Utilities::MPI::max.
Merge pull request #183 from bangerth/harden-mpi-reductions

Harden mpi reductions
Provide better documentation on ghosted vectors.

This includes a discussion of what ghosted vectors are and what their
semantics are.
Merge pull request #177 from bangerth/document-ghosted-vectors

Provide better documentation on ghosted vectors.