Allow Periods in Page Names

Thanks to Jeff Zellman.

lib/url_generator.rb

@@ -91,7 +91,6 @@ class UrlGenerator < AbstractUrlGenerator
   end
 
   def page_link(mode, name, text, web_address, known_page)
-    return %{<span class='wikilink-error'><b>Illegal link (target contains a '.'):</b> #{name}</span>} if name.include?('.')
     case mode
     when :export
       if known_page