- when an episode/report step is over, the next is started by endEpisode()
- the problem does not deal with updating the simulation time anymore
- rename `episodeIdx` in to `reportStepIdx` the 'EclWriter' because
this variable is -- and always has been -- the report step number
used by some parts of `opm-output`'s ECL writing code (the report
step number is equivalent to the episode index plus 1). IMO, the
output and parser code should be made more consistent in regard of
whether it expects 0-based or 1-based indices, but this is a story
for another day.