ENH: Refactor wet_bulb_temperature for performance
ENH: Refactor wet_bulb_temperature for performance

Take advantage of the fact that lcl supports operating on entire grids
to move it out of the loop. This shaves down the runtime for an average
profiles (~120 levels) by about 10%.

Unidata/MetPy,Unidata/MetPy,dopplershift/MetPy,dopplershift/MetPy