`CONUS-II` future products lack leap days

[kasra-keshavarz]

Unlike CONUS-II historical runs, the future runs lack leap days. This needs to be taken care of for its processes.

[kasra-keshavarz]

Resolved by #60

[kasra-keshavarz]

Additional comment from Logan Fang (University of Saskatchewan):

Regarding the leap years, when I extracted the historical simulation outputs three weeks ago, I found that there are no data for February 29 in leap years such as 1996, 2000, etc. From a discussion with another researcher, I found out that this is likely because the boundary forcing GCM is from CMIP5 that doesn't consider leap years and WRF must follow the date sequence of its forcing data.
There are a couple links on this issue:
https://rda.ucar.edu/datasets/ds612.5/#
https://forum.mmm.ucar.edu/threads/no-leap-years-run.9240/