Initial fix for issue 2555
Small modifications to enable keyword retrieval
Pass requested keywords as a string.
Allow multiple --key arguments
--keyword instead of --key
--keyword instead of --key
Support wcslib 4.24 in tests
Adds support for the fitsheader --table feature
Adds support for the fitsheader --table feature
Fix LooseVersion comparison.
Update WCS_VERSION in our local build.
Don't override system WCSVERSION
Simplified code and improved docstrings
Adds a test for the fitsheader --table feature
improved the usage string and tests
improved the usage strings and tests
initial checkin of new approach
just use subtracted angle
screwed up relative imports
oops, had double units on roll angle