Are changes needed to support a Gregorian (leap year) calendar?

_From @billsacks on April 8, 2016 1:25_

For now this is more of a question than an issue... we can change it into an issue if it seems warranted:

Do people feel that any changes are needed for CISM to support a Gregorian (leap year) calendar? Typically CESM operates with a NOLEAP calendar, but some applications use it with a Gregorian calendar.

I'm pretty sure that CISM currently assumes a 365-day (no-leap) calendar (e.g., the scyr parameter is hard-coded to 365 days). I could imagine this possibly causing small errors both in terms of averaging quantities sent to / from the climate model, and also in terms of the number and size of the dynamics timesteps that fit within a year.

There are really two questions:

(1) Are people concerned about the small (but systematic) errors this will cause?

(2) Might the current assumptions cause any major problems, such as causing the run to crash?

This one will probably take some experimentation. I'm not sure how to test this, which is part of my motivation for filing this as an issue to come back to later.

_Copied from original issue: E3SM-Project/cism-piscees#54_