Main issue is that missing values are not handled correctly.

also, create option to use existing hirs collo file, for faster testing

this was with 2x '--aggressive'

and add CrIS WV channels

multiple viirs granules actually works; multiple cris granules will not
(but it might not actually be too bad to support it)

runs w/o exception but data is junk.

though avhrr-specific-filestruct stuff is temporarily broken.