Merge pull request #1397 from nfagerlund/error_187_undefined_method_encoding_for_mailto

Fix 'undefined method `encoding` for "mailto"' errors w/ Ruby 1.8 and Kramdown > 0.14.0

lib/jekyll/converters/markdown/rdiscount_parser.rb

@@ -24,7 +24,9 @@ module Jekyll
         private
         def replace_generated_toc(rd, html, toc_token)
           if rd.generate_toc && html.include?(toc_token)
-            html.gsub(toc_token, rd.toc_content.force_encoding('utf-8'))
+            utf8_toc = rd.toc_content
+            utf8_toc.force_encoding('utf-8') if utf8_toc.respond_to?(:force_encoding)
+            html.gsub(toc_token, utf8_toc)
           else
             html
           end

lib/jekyll/core_ext.rb

@@ -69,11 +69,3 @@ module Enumerable
     any? { |exp| File.fnmatch?(exp, e) }
   end
 end
-
-if RUBY_VERSION < "1.9"
-  class String
-    def force_encoding(enc)
-      self
-    end
-  end
-end