remove :renderer from global pagination_options to discourage using it

Because lately it's popular to mount different web frameworks in the
same Ruby process (e.g. Sinatra apps beside Rails), a global link
renderer option is useless since it would affect all frameworks but it's
hardly possible that a single renderer will work in all of these
frameworks.

See resolution for mislav#176

lib/will_paginate/view_helpers.rb

@@ -28,7 +28,6 @@ class << self
       :link_separator => ' ', # single space is friendly to spiders and non-graphic browsers
       :param_name     => :page,
       :params         => nil,
-      :renderer       => nil,
       :page_links     => true,
       :container      => true
     }
@@ -49,8 +48,8 @@ class << self
     # * <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, class or instance of a link renderer (default:
-    #   <tt>WillPaginate::LinkRenderer</tt>)
+    # * <tt>:renderer</tt> -- class name, class or instance of a link renderer (default in Rails:
+    #   <tt>WillPaginate::ActionView::LinkRenderer</tt>)
     # * <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)

lib/will_paginate/view_helpers/link_renderer.rb

@@ -35,7 +35,7 @@ def to_html
       # Returns the subset of +options+ this instance was initialized with that
       # represent HTML attributes for the container element of pagination links.
       def container_attributes
-        @container_attributes ||= @options.except(*(ViewHelpers.pagination_options.keys - [:class]))
+        @container_attributes ||= @options.except(*(ViewHelpers.pagination_options.keys + [:renderer] - [:class]))
       end
 
     protected