Fixing problems with MGConstrainedDoFs
implement deprecated get_refinement_edge_boundary_indices()
use new logic in multigrid assemblers and switch step 16 to MeshWorker
all existing multigrid tests verified with fixed MGConstrainedDoFs
new test for Neumann data
Correct a minor violation of coding standards.
Fix a typo...
Merge pull request #44 from oneliefleft/master

Correct a minor violation of coding standards in Petsc wrappers
Update documentation of step 16
Fix minor issues in multigrid tests
Merge pull request #43 from guidokanschat/new_multigrid_tests

Fix logical problems in MGConstrainedDoFs and rewrite step 16
Add empty virtual destructors for TimeStepping and RungeKutta.
Merge pull request #46 from Rombur/time_step_petsc

Add empty virtual destructors for TimeStepping and RungeKutta.
Testsuite: Move forgotten file to correct location

All testsuite stuff is now under ./tests. Consequently,
macro_pickup_tests.cmake should also be moved.
Testsuite: Update a comment
Testsuite: Also use '<>=,' as numdiff separators

This commit addresses issue #38: We have several tests in which numdiff
fails to recognize a number, because the output contains some unknown
delimiters, such as one of "<>=,".
Fix an outdated reference to fparser. Add a link.
More fixes with references that are now outdated.
Merge pull request #47 from tamiko/address_testsuite_issues

This pull_request addresses several minor issues with the testsuite:
Merge pull request #48 from bangerth/doc-fixes-5

Fix an outdated reference to fparser. Add a link.
Fix an instantiation.

The existing instantiation works, but is not in line with the actual
declaration of the function. This may or may not be the problem with
the failing tests here http://cdash.kyomu.43-1.org/viewTest.php?onlyfailed&buildid=10664
that result from a missing instantiation.