TWP/SKYRAD/C2 - IRT bias

The IRT was measuring higher sky temperatures than AERI. The problem was corrected by 
changing the mirror.

• Sky Infra Red Temperature Maxima(sky_ir_temp_max)
• Sky Infra-Red Temperature(sky_ir_temp)
• Sky Infra-Red Temperature Minima(sky_ir_temp_min)
• Sky infrared temperature, standard deviation(sky_ir_temp_std)