Fixes rdoc issue #170 by Thomas Leitner.
* test/rdoc/test_rdoc_servlet.rb:  Test for above.

* lib/rdoc/code_object.rb:  Split #initialize_visibility from
  #initialize for reuse when loading a stored object.
  Fixes rdoc issue #171 by Thomas Leitner.

* lib/rdoc/any_method.rb:  Initialize visibility for #display?  For
  rdoc issue #171
* lib/rdoc/attr.rb:  ditto.
* lib/rdoc/class_module.rb:  ditto.
* lib/rdoc/top_level.rb:  ditto.
* test/rdoc/test_rdoc_any_method.rb:  Test for above.
* test/rdoc/test_rdoc_attr.rb:  ditto.
* test/rdoc/test_rdoc_class_module.rb:  ditto.
* test/rdoc/test_rdoc_constant.rb:  ditto.
* test/rdoc/test_rdoc_top_level.rb:  ditto.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38899 b2dd03c8-39d4-4d8f-98ff-823fe69b080e