[fitsbits] Celsius unit in FITS keyword comments

[Forveille thierry]

  On 03/03/2016 01:35 PM, Rob Seaman wrote:
>   In the absence of recognized units a comment should probably spell things out verbosely, so perhaps something like:
>
> 	"/ [deg C] temperature in degrees Celsius”
>
>
Or much preferably, just convert to Kelvins. Nobody (hopefully) would 
write a pressure
in pounds/square inch in a FITS file, and Celsius falls into the same 
bin of non-supported
units.