RFM v5 Updates

5.30 01AUG25: This release is mostly because of a significant internal restructuring of the code, and no doubt includes a whole new set of bugs. Generally there is no need to use it in preferenc to v5.22 unless you particularly need some of the new features

5.22 17APR25: This a consolidated version of the current RFM prior to a major internal restructure.

5.12 03DEC21

5.10 23MAY20: New Features

Major internal restructuring, so v5.10 rather than v5.04
Diffuse surface reflection (as well as specular) (*SFC section, RFLSFC)
Different length units for homogeneous paths (ie not always in km) (*TAN section, UNITS)
Generalised handling Collision Induced Absorption files (*CIA section)
Observer altitude may be replaced by pressure level (*OBS section, PREOBS)
RFM-basic alternative HITRAN line data structure for line-mixing
Simplified definition of transmittance etc for nadir viewing over — no longer depends on whether surface is reflective or not.
Remove 'feature' of returning NaN radiances for wavenumbers close to 0 (caused by Planck function not having an asymptotic form for small wavenumber limit).

5.03 09MAR20: New Features; None, this is just a collection of bug fixes for the v5.02 code.; Bug Fixes:

Bug#16 - Bug#26

5.02 01FEB19

Additional GEISA molecules
Updated H2O continuum model, courtesy of Keith Shine (U.Reading) - now uses MT_CKD v3.2 instead of v2.5 (change parameter USEC25 in subroutine spcctm_sub.f90 from .FALSE. to .TRUE. if you want to revert to the MT_CKD v2.5 continuum model.

5.01 01JUN18

Redefine molecule #48 as C2N2 (was C3H8) for consistency with HITRAN 2016 (#49 COCl2 unchanged). Note that HITRAN 2016 only defines molecules up to #49.
Also redefine #50 SO (was BrO), #51 C3H4 (was GeH4), #52 CH3 (was C3H8), #53 CS2 (was C2N2) for consistency with 2016 TIPS
Molecues#54-56 no longer defined (I'll catch up on the extra GEISA molecules in a later update).
Include new HITRAN 2016 isotopes: H2O 262, CO2 737.