Add --changelog option to gem install/update command
Merge pull request #2 from KitaitiMakoto/show-on-install-pr

Add --changelog option to gem install/update command
Explicitly require rubygems/security.rb

Requiring rubygems/install_update_options.rb introduces (empty) Gem::Security.
In rubygems 2.0.3+, Gem.clear_paths calls Security.reset if Security is defined.
Bump the version