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Remove an outdated TODO, leave a new one.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.
simpler material model
add test for simpler
manual updates: extract all .prms

We now auto-generate the annotated .prm.out files from the .prm files when you
make manual.pdf. All prm snippets in the manual now live in external
files. This patch also contains updates to the benchmark section explaining
how to compile the shared libs for the benchmarks.

This is a combination of 9 commits:
extract more prms from manual
manual: add section explaining benchmark compilation
add missing .prm
change to more safe escaping in .prm for manual
final batch of prms extracted from the manual
rename sol_cx.prm and improve manual
rename sol_kz prm
remove all .out and generate them on demand instead
update .gitignore
Merge pull request #75 from tjhei/manual_updates

Manual updates
fix error message formatting in cmake project
Merge pull request #76 from tjhei/simpler_model

Implement simpler model
Augment documentation slightly.
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