add opm-parser and dune-cornerpoint as optional dependencies
build system: add ERT config.h variable and explicitly check for boost

(boost is required for the to_upper_copy() function.)
clean up the output writing routines

this is required to make them multi-format capable...
refactoring: extend the TimeManager to become the Simulator

this also comes with moving responsibilities around and some smaller
cleanups for the grid creation. (although grid creation could be
possibly done by the simulator now, the GridCreator concept has not
been abandoned, yet...)
fix the calculations which need the current time step size

this did not work correctly for very large time step sizes like
1e100...
add a writer for Eclipse binary output files

This uses the ERT libraries and currently only works for the blackoil
model in conjunction with the element centered finite volume
discretization and Dune::CpGrid (from the dune-cornerpoint OPM
module).
add a simulator which uses Eclipse data files and the blackoil model
clean up the BlackOilProblem and actually use it...
black oil model: Add some assertations
add the possibility to disable the VTK output globally

this is easier than setting the parameters for all inividual quantities to
false and also does not produce the useless glue file (the .PVD file)...
refactoring: rename GridCreator to GridManager

because "manager" sounds less religious than "creator" and the
GridCreators did all kinds of other stuff besides creating the grid.

this patch also gets rid of the static function inside these classes,
which should make them easier to understand...
ECL simulator: use the report steps from the deck
make the name() method of problems non-static again

this allows to easily specify the problem name at runtime.
ECL problem: return the stem of the name of the deck file in the name() method

this causes output files to have the expected names, e.g. "SPE9" or
"NORNE" instead of "ECL"...
Simulator: Make the time of the start of the simulation retrievable
ECL problem: set the start time to the one specified in the deck
EclipseWriter: Write restart files

this means we now write the current solution to the Eclipse output
files.

TODO: summary files. (this depends on having a well-model.)