OpenImageIO/oiio — pull request #332 by c42f (2012-04-19 13:33:36+00:00)
Title: Fix oiiotool argument help + add man page generation

As mentioned on the mailing list, oiiotool man page generation was not being performed.

It was very easy to add this, but in the process I also found that some oiiotool command line options had empty doc strings, which caused them to be completely ignored in the usage information given by "oiiotool --help". Fix this here by copying over the associated doc strings from idiff, and updating for the more general context.