Merge branch '43-allow-to-simulate-a-subperiod-without-discharge-in-simgr' into 'dev'

Resolve "Allow to simulate a subperiod without discharge in SimGR"

Closes #43

See merge request !19
3 jobs for dev in 6 minutes and 14 seconds (queued for 7 seconds)
Status Name Job ID Coverage
  Check
passed check_as_cran_devel #192418

00:01:56

passed check_as_cran_oldrel #192419

00:01:56

passed check_as_cran_patched #192417

00:02:22