New radiation package

[oyvindseland]

Made a separate discussion point from
#186

Will likely have to be split up into several tasks so keeping it as a discussion for now.
-Should we try to use the old interface calls to radiation, i,e shadow files
-Create new interface that use more of the original subroutines.
-Check wavelength bands.
-Do we need to modify Aerotab
-Do we need to modify the table look-up