DIR/DIF surfaces fluxes are available as outputs:

DIR/DIF surfaces fluxes are available as outputs:
   - either directly computed in Goddard and RRTMG
   - or from regressive equation when Goddard or RRTMG is not used

Interpolation of short-wave radiation is added based on the updated solar zenith angle between SW call.It must be activated in the namelist with the new physics option swint_opt. This option is being included as a global attribute of the wrfout so the user knows whether it was used or not

Previous code changes:
Computation of cosine of sza was wrapped in a single function so it will make easy to centralize and homogeneize all these computations in future updates. Equation of time correction was included in the sza computations

Affect files:
M       phys/module_ra_goddard.F
M       phys/module_radiation_driver.F
M       phys/module_ra_sw.F
M       phys/module_ra_rrtmg_sw.F
M       share/output_wrf.F
M       Registry/Registry.EM_COMMON
M       dyn_em/module_first_rk_step_part1.F

git-svn-id: https://svn-wrf-model.cgd.ucar.edu/trunk@6817 b0b5d27b-6f0f-0410-a2a3-cb1e977edc3d