Description:
    Stubs out a new plugin at vendor/plugins. Pass the plugin name, either
    CamelCased or under_scored, as an argument.

Example:
    `rails generate plugin BrowserFilters`

    creates a standard browser_filters plugin:
        vendor/plugins/browser_filters/README
        vendor/plugins/browser_filters/init.rb
        vendor/plugins/browser_filters/install.rb
        vendor/plugins/browser_filters/lib/browser_filters.rb
        vendor/plugins/browser_filters/test/browser_filters_test.rb
