update to the devel release (20211204b), to become production

[Jeremy Faden]

I've made an update to the development release which I expect will
become the production release sometime after Monday.  It's mostly a
number of bugfixes to the new GUIs for editing labels and tick
positions.  It does fix a convenient feature to grab colors off of the
screen instead of scanning through lists of colors or trying to match it
by eye.  There's also a new feature where XML and JSON files are now
inspected to automatically detect the reader which should be used.  So
for example you can point to a PDS4 XML file and it knows to use the
PDS4 reader, and similar for TFCAT JSON files.

This is the devel version at autoplot.org, or
http://autoplot.org/jnlp/20211204b/.

Jeremy