Made compositional IC plugins ready for being derived from SimulatorAccess.

Removed the geometry_model pointer that was stored as default in interface.cc
Remove an outdated TODO, leave a new one.
Unified the handling of initial conditions to other plugins.

Previously used pointers to geometry_model, adiabatic_conditions and
boundary temperature were removed and replaced by calls to
SimulatorAccess as in all other plugins. This will break user-defined
plugins, which use these pointers.
Make message look uniform.
Give an indication of how many tests we have.
Make message look uniform.
log number of inner iterations in Stokes preconditioner
update test outputs
Merge pull request #83 from tjhei/solver_statistics

Solver Statistics
Sort the names of plugins.

Sort the names of plugins in the documentation. Upon visual inspection, also fix a number of formulas and text issues found in the manual's description of the various plugins.
Merge pull request #84 from bangerth/sort-model-names-try-2

Sort the names of plugins.
fix test output
make update_parameters.sh script more robust
Merge pull request #88 from tjhei/fix_a_test

fix test output
fix doxygen formatting in header
comment wrapping, doxygen formatting
run astyle
wrap comments again
fix copyright year
Changed an Assert to an AssertThrow.