Use a trick by Martin Kronbichler to accelerate matrix operations in parallel.

This tells deal.II to use a structure on the side to facilitate faster writing into
matrices when doing computations in parallel.
These should be lowercase.
Add a check to avoid this bug.
Merge pull request #217 from bangerth/accelerate-sparsity-pattern

Use a trick by Martin Kronbichler to accelerate matrix operations in parallel
Make sure <link.h> exists before using it.
Merge pull request #219 from ian-r-rose/fix_typo

Fix bug in multicomponent
fix test output

some differences were introduced in the multicomponent* tests and the other tests
 changed due to some configuration change.
Merge pull request #220 from bangerth/verify-link.h-existence

Make sure <link.h> exists before using it.
Merge pull request #221 from tjhei/fix_tests

fix test output