Use deck_filename to reference the deck

Bring the examples into the same line as the examples in opm-core by
using deck_filename as the name of the parameter which identifies the
deck input files.
Add Eclipse output to example

This is an example of how writing Eclipse output files can be added to
the generic 3D simulator.
Write output of simulator for every reporting time

The output object will connect itself to the simulator. Theoretically,
there is a race condition since the output will be destroyed before the
simulator, but this will never happen because the simulator won't
signal any timestep events after its timestepping loop.
Merge pull request #52 from rolk/052_eclout

Add Eclipse output to example