update to the development release 20220521a

[Jeremy]

I've made an update to the Autoplot development release.  This should become the next production release.  This includes a correction to fix a bug, there changing the display type (spectrogram to stack of lines) would immediately revert back.  I can't recall what required the change which caused the bug, but clearly this is more fundamental to how Autoplot is supposed to work.  This also corrects a problem where the FFTPower would not apply a frequency translation properly, a mechanism used infrequently that had been broken at some point.  I'll be sure to get this into the regular testing so there won't be another regression.

This also contains new code to read STS files, which are a type of ODL files used by some teams to store magnetic field data. And, the pngwalk quality control (QC) tool now provides options to view only the files marked as okay or marked as a problem, where before you had to look at both at once, or all image files, (including unmarked ones).

This is the Autoplot devel release, at http://autoplot.org/jnlp/devel/.

Jeremy