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Patch by Jacqueline Austermann: Update the dynamic topography postprocessors.
Fix a number of text issues.
Run astyle on the new files.
Rename a member variable to conform to common style. Fix a text issue.
Add a new test.
Run only a single time step.
Add the correct output files for this test.
Document changes.
Merge pull request #22 from bangerth/new-dynamic-topography

Changes by Jacqueline Austermann: Implement an improved postprocessor for the dynamic topography, taking into account the dynamic pressure.
Merge pull request #21 from bangerth/fixes

Document the simple material model (and other related and assorted fixes).
Remove a commented out token that is a left-over from previous commits.
Minor simpifications.
Escape underscores so that they can be input into the latex manual without further change.
Escape underscores so that they can be input into the latex manual without further change.
Greatly extend the documentation of the 'simple' material model to explicitly say what it actually does.
Undo two parts of previous changes since there is apparently a script
(update_parameters.sh) that does these transformations automatically.
Merge branch 'master' of https://github.com/geodynamics/aspect into fixes