# Renders Digg/Flickr-style pagination for a WillPaginate::Collection
    # object. Nil is returned if there is only one page in total; no point in
    # rendering the pagination in that case...
    #
    # ==== Options
    # * <tt>:class</tt> -- CSS class name for the generated DIV (default: "pagination")
    # * <tt>:prev_label</tt> -- default: "« Previous"
    # * <tt>:next_label</tt> -- default: "Next »"
    # * <tt>:inner_window</tt> -- how many links are shown around the current page (default: 4)
    # * <tt>:outer_window</tt> -- how many links are around the first and the last page (default: 1)
    # * <tt>:separator</tt> -- string separator for page HTML elements (default: single space)
    # * <tt>:param_name</tt> -- parameter name for page number in URLs (default: <tt>:page</tt>)
    # * <tt>:params</tt> -- additional parameters when generating pagination links
    #   (eg. <tt>:controller => "foo", :action => nil</tt>)
    # * <tt>:renderer</tt> -- class name of the link renderer (default: WillPaginate::LinkRenderer)
    # * <tt>:page_links</tt> -- when false, only previous/next links are rendered (default: true)
    # * <tt>:container</tt> -- toggles rendering of the DIV container for pagination links, set to
    #   false only when you are rendering your own pagination markup (default: true)
    # * <tt>:id</tt> -- HTML ID for the container (default: nil). Pass +true+ to have the ID automatically
    #   generated from the class name of objects in collection: for example, paginating
    #   ArticleComment models would yield an ID of "article_comments_pagination".
    #
    # All options beside listed ones are passed as HTML attributes to the container
    # element for pagination links (the DIV). For example:
    #
    #   <%= will_paginate @posts, :id => 'wp_posts' %>
    #
    # ... will result in:
    #
    #   <div class="pagination" id="wp_posts"> ... </div>
    #
    # ==== Using the helper without arguments
    # If the helper is called without passing in the collection object, it will
    # try to read from the instance variable inferred by the controller name.
    # For example, calling +will_paginate+ while the current controller is
    # PostsController will result in trying to read from the <tt>@posts</tt>
    # variable. Example:
    #
    #   <%= will_paginate :id => true %>
    #
    # ... will result in <tt>@post</tt> collection getting paginated:
    #
    #   <div class="pagination" id="posts_pagination"> ... </div>
    #