per SIFT/sift#173 request from TimS

Also refine further attributes like production site

min(0, value) needed to be max(0, value)

Still needed: a LUT for some of the L2 attributes missing

It should be "ABI Cloud and Moisture Full Disk Imagery" for instance
Failure to degrade to using :scene_id from L1B when --scene is not provided.

Example:
$PYTHON -m goesr.cmi_changer -vv -R F -S Full\ Disk -E OR -C -a "version='cmi-testing'" --attribute "coupon=8675309" --attribute "ncc1701_d=engage" -d $* $input

/Users/keoni/anaconda/envs/sat/bin/python3 -m goesr.cmi_changer -vv -R F -S 'Full Disk' -E OR -C -a 'version='\''cmi-testing'\''' --attribute coupon=8675309 --attribute ncc1701_d=engage -d input/IMG_DK01B09_201703300210.bz2
WARNING:__main__:could not evaluate 'engage', assuming string attribute
INFO:__main__:additional attributes: OrderedDict([('version', 'cmi-testing'), ('coupon', 8675309), ('ncc1701_d', 'engage')])

needed for SIFT >0.9.4 reading of HSD/HCAST as CMI

still need better handling of multi-band possibility

since we should be producing a band_id dimension for CMI

may need additional tweaks for HSD channels

reviewed nc_compare_schema output vs actual CMIP files

HCAST example
python -m goesr.cmi_changer -vv -R F -S Full\ Disk -E OR -C $* input/IMG*

e.g.
 OR_AHI-L2-CMIPF-M1C09_H8_s20170330021021_e20170330021940_c20170929174832.nc