Update to Treat RH as a Unitless Ratio in Existing Functions
Update to Treat RH as a Unitless Ratio in Existing Functions

As discussed in PR #669, for consistency with the rest of the library, relative humidity should be treated as a unitless ratio in [0, 1]. It was noticed that some previous functions in thermo.py treated it as a percentage. This aims to correct that.

Unidata/MetPy,jrleeman/MetPy,jrleeman/MetPy,Unidata/MetPy,dopplershift/MetPy,ahaberlie/MetPy,ShawnMurd/MetPy,ahaberlie/MetPy,dopplershift/MetPy