Standardize date/time variables in set_env and common run scripts

[fossell]

Date/Time information (startdate, fhr, etc.) are set multiple times in set_env for each component sincce each component run script historically used a different environmental variable name.

Consolidate these into one setting of date/time in set_env and modify run scriptst to use the same environmental variable name.

[fossell]

This may not be as straight forward as we hoped due to quite a bit of customization/flexibility in processing different dates/times for each component for different cases. Examples:

Sandy: Same start date, start fhr, end fhr for all components. But fhr increment is 1 hour for UPP and Python, but only 3 hourly for MET (assuming due to obs availability; and for Snow case).

Derecho: Same start date and beg fhr, end fhr, and fhr increment for WRF, UPP, Python, MET for d01. But for d02, different beg fhr and end fhr for UPP.

Just with these two examples, it's really only possible to set startdate once and unify that variable. The other variables, well, vary, too much across components and cases. One thing we could do, is at least make all the same variales in set_env.ksh be the same name, e.g. unify startdate, START_TIME, init_time all to be "START_TIME" or whatever is decided. At least then they are all the same variable when setting them .

Suggest a discussion or input from team regarding how to proceed.