Reorg NEWS
RELEASEGUIDE: Minor clarification
docs: Clean up LRO-NAC example documentation

Elaborate more in the paragraphs and fix formatting so code actually
fits on page.
docs: Elaborate on lronac2mosaic documetation
NEWS: Minor spell
AUTHORS: Added self, Scott. Zack is lead, sans PI
INSTALLGUIDE: Large overhaul
NEWS: Reword
Documentation changes
More doc changes
Docs: More tweaks
Tagging 2.3.0 and last touches
RELEASEGUIDE: Expand on how to tag/untag
RELEASEGUIDE: More on how to tag/untag
pc_align: Bugfix: Origin must be planet center when calc lon,lat offset
sparse_disp.in: double the dilate radius

We were dilating the quality mask by coarse_skip/2.  This leaves gaps, which should go away if we double the kernel width.
sparse_disp: add debugging options, catch bad-match errors

-Can now specify -D to get an output csv of disparity points, a second csv of points that have failed with an indication of why they failed, plus chit-chat from the script as it runs

-Errors where norm_xcorr returned 'None' were getting passed through as zero-disparity points.  These should have been deleted.
sparse_disp: change success criteria

1. increase teh default epipolar tolerance
2. allow the minimum maximum-disparity value  to be specified
sparse_disp: remove testing and SSD code for the norm_xcorr code
sparse_disp: change epipolar test

epipolar test now compares ep_dist to the maximum of ep_tol and 0.02*abs(disp-median_disp).  This lets us use a smaller default ep_tol and seems to give cleaner results