* Extract RSS and REXML into separate subpackages, because they were moved from
default gems to bundled gems.
* Obsolete Net::Telnet and XMLRPC packages, because they were dropped from Ruby.
The detailed changelog leading to this release is preserved in
private-ruby-3.0 branch.
Move gemified xmlrpc into subpackage.
Move gemified openssl into subpackage.
Tk is removed from stdlib.
Extend 'gem_' macros for pre-release version support.
- Explicitly list RubyGems directories to avoid accidentaly packaged content.
- Split test-unit and power_assert gems into separate sub-packages.
- Drop libdb dependency in favor of gdbm.
