Command line utility should support stereo geometry plot creation from XMLs, before running ASP

[dshean]

Hoping to make some quick stereo geometry plots for candidate image pairs using CLI. I don't think this is possible right now.

Note that directory structure might not always be nice and clean, and XML with relevant metadata could be 3 or 4 subdir deep, with other XML files (like README.XML) in the directory that should be ignored.

Will require rewriting legacy dgtools code in stereopair_metadata_parser.py. We should not assume that CATID is in the filenames. And a user should be able to run something like geom_plot *.XML without expected directory structure and filename patterns.

Eventually, the geometry plot tool should be flexible enough to also support multiple images (not just a pair), like the Utqiagvik 7 pair geometry skyplot, or just a list of individual image dir or XML files. Needed for multi-view goemetry assessment. Can discuss design for this.