add a test for the direct parallel PETSc solver

which is using MUMPS right now.
Silence linear solver fails from all but processor zero.

 When a linear solver fails to converge in a parallel program, every processor would output the same error message -- leading to incredible amounts of entangled error messages. This has now been resolved: every processor still fails, but only processor 0 reports the error.
Add S40RTS initial condition

This is a combination of 5 commits:
Adding scripts to perturb the initial temperature field according to S40RTS
Included spline.h into S40RTS_perturbation.h and S40RTS_perturbation.cc file. Added tests for S40RTS and S20RTS
Updates for prescribed S40RTS initial temperature condition
Updated cos_coeffs, sin_coeffs and spline_depths function
Updated tests
Removed merge conflict from screen-output files
Merge pull request #125 from bangerth/silence-solver-fails

Silence linear solver fails from all but processor zero.
Merge pull request #124 from jaustermann/s40rts

Add S40RTS initial condition
Merge remote-tracking branch 'cig/master'
fix test output for S40RTS tests
update changelog.h and add Jacky to the manual.tex
remove accidentally added broken test
sane number of solver iterations
Merge pull request #127 from tjhei/sane_solver_iterations

sane number of solver iterations
add missing changelog entry
cleanup refine_mesh code in core.cc

Avoid initializing unused vectors, cleaner SolutionTransfer code,
formatting.
report convergence failures in release mode

A recent change causes the linear solvers to hang in release mode (with
more than one process) if we don't reach convergence.
Merge pull request #129 from tjhei/fix_solver_errors

report convergence failures in release mode
Merge pull request #128 from tjhei/core_cc_formatting

cleanup refine_mesh code in core.cc
Writing &(variable) always strikes me as wrong because things in parentheses
are expressions, and taking the address of an expression should yield, at
best, a lambda function. I know that's pedantic but I know I'm a pedant and
the patch makes me happy!
Merge pull request #130 from bangerth/expressions-are-not-variables

Writing &(variable) always strikes me as wrong because things in parenth...
implement denormalize_pressure() for direct solver