known bug: *.java matches ".java". The unix glob behavior is to require that a leading . must be explicitly matched.
converts regex into a glob, as best it can.
converts a glob into a Pattern.
converts a glob into a regex.
unglob the glob into an array of the matching FileObjects. See sftp://papco.org/home/jbf/ct/autoplot/script/demos/filesystem/unGlobDemo.jy