Passing keys to the restart load function.
Followup to: https://github.com/OPM/opm-output/pull/152
Previously the list of keywords to load from a restart file was hardcoded in the opm-output, now the `load_from_restart_file( )` takes a map of keys to load. With the current follow-up patch the hardcoding has just been moved into the opm-simulator.
jenkins build this opm-output=152
> jenkins build this opm-output=152
Has this jenkins fellow relaxed the stiff upper lip slightly; i.e. no longer requiring *please*?
jenkins build this opm-output=152 please