HACK: work around empty raw messages
README: set expectations
make duplicate matching fuzzy w/r/t line number

Almost all (HDL) source code changes result in renumbering of line
number; this means the line number of errors will be different, which
was causing diff matching to break.

The changes in this commit also affect xmsgsprint for consistency.
fix crash bug when 'delta' not defined
fix bug with globbing on _xmsgs directory

Also, be more persistent looking for subdirectories.
bump to 0.2.1