SGP/MFR/C1 - Failed heater board

The heater board began showing signs of failure on 20150503.  These are times when the 
head temp has noise.  It's obvious when looking at a plot.  When boards fail it's often a 
slow death.  Best to avoid data covered by this DQR.

Do not use data

• 3 meter upwelling broadband hemispheric irradiance(up_hemisp_broadband)
• 3 meter upwelling narrowband hemispheric irradiance, filter 2, offset corrected(up_hemisp_narrowband_filter2)
• 3 meter upwelling narrowband hemispheric irradiance, filter 3, offset corrected(up_hemisp_narrowband_filter3)
• 10 meter upwelling narrowband hemispheric irradiance, filter 1(up_hemisp_narrowband_filter1)
• 10 meter Narrowband Upwelling Hemispheric Irradiance, Filter 6(up_hemisp_narrowband_filter6)
• 3 meter upwelling narrowband hemispheric irradiance, filter 4(up_hemisp_narrowband_filter4)
• 25 meter upwelling narrowband hemispheric irradiance, filter 5, offset corrected(up_hemisp_narrowband_filter5)

• 3 meter upwelling broadband hemispheric irradiance(up_hemisp_broadband)
• 25 meter upwelling narrowband hemispheric irradiance, filter 5, offset corrected(up_hemisp_narrowband_filter5)
• 3 meter upwelling narrowband hemispheric irradiance, filter 4(up_hemisp_narrowband_filter4)
• 10 meter Narrowband Upwelling Hemispheric Irradiance, Filter 6(up_hemisp_narrowband_filter6)
• 10 meter upwelling narrowband hemispheric irradiance, filter 1(up_hemisp_narrowband_filter1)
• 3 meter upwelling narrowband hemispheric irradiance, filter 3, offset corrected(up_hemisp_narrowband_filter3)
• 3 meter upwelling narrowband hemispheric irradiance, filter 2, offset corrected(up_hemisp_narrowband_filter2)

• (Raw data stream - documentation not supported)