Revert to reading I3 met fields each hour instead of once per day

Reading met fields once per day was causing issues in the instantaneous
met fields starting at hour 21:00 of each day because HEMCO hasn't read
the next day's data yet. We have restored the settings in HEMCO_Config.rc
to read met fields hourly with the appropriate offset. In addition, we
reverted to reading the I3 met fields separately at the beginning and end
of timestep (e.g. SPHU1 and SPHU2 instead of just SPHU2).

Signed-off-by: Melissa Sulprizio <[email protected]>