Description:
    Stubs out a new plugin. Pass the plugin name, either CamelCased or
    under_scored, as an argument. Pass --with-generator to add an example
    generator also.

    This creates a plugin in vendor/plugins including an init.rb and README
    as well as standard lib, task, and test directories.

Example:
    `./script/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
        vendor/plugins/browser_filters/tasks/browser_filters_tasks.rake

    ./script/generate plugin BrowserFilters --with-generator

    creates a browser_filters generator also:
        vendor/plugins/browser_filters/generators/browser_filters/browser_filters_generator.rb
        vendor/plugins/browser_filters/generators/browser_filters/USAGE
        vendor/plugins/browser_filters/generators/browser_filters/templates/