mjucker/MiMA: MiMA v1.0 bugfix

This is a bugfix release, with the most notable updates being:

• Short wave radiation bugfixes (thanks to Stephen Thomson @sit23 for pointing those out)
  • The diurnal average of cosine of zenith angle (coszen in atmos_param/rrtm_radiation/astro.f90) had a bug. This is a rather large effect at high latitudes. In particular, sunlight didn't reach high latitudes in winter, making the polar vortex too strong. With the correction coming in this version, the daily averaged cosine zenith angle is exactly the same as a daily average of zenith angles evaluated at discrete time steps.
  • The zenith angle calculation did not account for the fraction of the averaging time step that actually sees daylight. This has been corrected with the introduction of the calculation of fraction of time of the averaging time step that a given grid point sees day, called fracday. The effect of this is minor.
• New diagnostics: Within the radiation module rrtm_radiation, two additional diagnostics are now available: olr, which is the Outgoing Longwave Radation, and isr, which is the net Incoming Short wave Radiation.