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Remove an outdated TODO, leave a new one.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.
fix doxygen formatting in header
comment wrapping, doxygen formatting
run astyle
wrap comments again
fix copyright year
Changed an Assert to an AssertThrow.
Merge pull request #86 from gassmoeller/simulator_access_initial_conditions

Simulator access initial conditions
Merge pull request #89 from tjhei/fixes

Code formatting and astyle
Made AdiabaticConditions a plugin architecture as well.

This resulted in changes to some material models since we no
longer can ask whether get_adiabatic_conditions returns a null
pointer (it will never do now), but instead we need to ask whether
the adiabatic conditions are already calculated, which is a function
that every adiabatic conditions plugin must implement.
Leave a comment.
Use correct ifdef name.
Documentation updates.
Allow initial conditions plugins to override the initialize() function.
Let InitialProfile create a constant AdiabaticProfile.
Since we have a valid default value, we do not need to try-catch.
Activate the update function for AdiabaticConditions.
Updated documentation and marked functions as virtual.