Scope the Unicode module so NameErrors make more sense.
Handle another case of the 'unicode' gem breaking things on JRuby.

This is was an omission from pull request #2315.
Merge pull request #2318 from nirvdrum/more_unicode_jruby_cleanup

More unicode jruby cleanup.
Added a JRuby workaround in a test that's failing due to a JRuby bug.
Bound the 'myns' XML namespace to keep Nokogiri on JRuby happy.

It appears JRuby's Nokogiri implementation is strict about using unbound XML namespaces.  Since a well-formed doc should have bound namespaces, I just added it here.
Merge pull request #2319 from nirvdrum/jruby_test_fixes

JRuby test fixes.