As a frequent user of the rmport script, it was time for some improvements:

• allow PORTSDIR to be a symbolic link when looking for expired ports or dependent ports
• allow for trailing slashes when specifying ports as cat/name. This prevents the port being a false positive for itself when the Makefile mentions the port name (e.g., in PLIST_FILES)
• fetch possibly open PRs via Bugzilla, GNATS is long gone. Remove the version that used freefall. Thanks to crees for pretty-printing the results.
• forcibly delete the temporary checkout to prevent rm(1) from asking for confirmation on each file in .svn
• add myself as author

Approved by: maintainer (crees)
Differential Revision: https://reviews.freebsd.org/D6396