Remove dependency on Redcarpet

Now Gollum does all its Markdown processing through GitHub::Markup; if
you require a custom Markdown renderer using Redcarpet or another
library, you can hot-load it from your own code base:

	Gollum::Wiki.markup_classes[:markdown] = YourRedcarpetRenderer

lib/gollum/markup.rb

@@ -433,51 +433,4 @@ module Gollum
     def update_cache(type, id, data)
     end
   end
-
-  begin
-    require 'redcarpet'
-
-    class MarkupGFM < Markup
-      def render(no_follow = false)
-        sanitize = no_follow ?
-          @wiki.history_sanitizer :
-          @wiki.sanitizer
-
-        data = extract_tex(@data.dup)
-        data = extract_code(data)
-        data = extract_tags(data)
-
-        flags = [
-          :autolink,
-          :fenced_code,
-          :tables,
-          :strikethrough,
-          :lax_htmlblock,
-          :no_intraemphasis
-        ]
-        data = Redcarpet.new(data, *flags).to_html
-        data = process_tags(data)
-        data = process_code(data)
-
-        doc  = Nokogiri::HTML::DocumentFragment.parse(data)
-
-        doc.search('pre').each do |node|
-          next unless lang = node['lang']
-          next unless lexer = Pygments::Lexer[lang]
-          text = node.inner_text
-          html = lexer.highlight(text)
-          node.replace(html)
-        end
-
-        doc  = sanitize.clean_node!(doc) if sanitize
-        yield doc if block_given?
-
-        data = doc_to_html(doc)
-        data = process_tex(data)
-        data
-      end
-    end
-  rescue LoadError
-    MarkupGFM = Markup
-  end
 end

lib/gollum/wiki.rb

@@ -54,32 +54,30 @@ module Gollum
       # Gets the markup class used by all instances of this Wiki.
       # Default: Gollum::Markup
       def markup_classes
-        @markup_classes ||
+        @markup_classes ||=
           if superclass.respond_to?(:markup_classes)
             superclass.markup_classes
           else
-            classes = Hash.new(::Gollum::Markup)
-
-            # Add custom markup classes for different languages
-            classes[:markdown] = ::Gollum::MarkupGFM
-            classes
+            Hash.new(::Gollum::Markup)
           end
       end
 
       # Gets the default markup class used by all instances of this Wiki.
       # Kept for backwards compatibility until Gollum v2.x
-      def markup_class
-        markup_classes[:default]
+      def markup_class(language=:default)
+        markup_classes[language]
       end
 
       # Sets the default markup class used by all instances of this Wiki.
       # Kept for backwards compatibility until Gollum v2.x
       def markup_class=(default)
-        new_classes     = Hash.new default
         @markup_classes = Hash.new(default).update(markup_classes)
         default
       end
 
+      alias_method :default_markup_class, :markup_class
+      alias_method :default_markup_class=, :markup_class=
+
       # Gets the default sanitization options for current pages used by
       # instances of this Wiki.
       def sanitization

test/test_wiki.rb

@@ -11,13 +11,17 @@ context "Wiki" do
     assert_equal Gollum::Markup, Gollum::Wiki.markup_class
   end
 
-  test "#markup_class= doesn't clobber alternate markups" do
+  test "#default_markup_class= doesn't clobber alternate markups" do
     custom = Class.new(Gollum::Markup)
-    Gollum::Wiki.markup_class = custom
+    custom_md = Class.new(Gollum::Markup)
 
-    assert_equal custom, Gollum::Wiki.markup_class
+    Gollum::Wiki.markup_classes = Hash.new Gollum::Markup
+    Gollum::Wiki.markup_classes[:markdown] = custom_md
+    Gollum::Wiki.default_markup_class = custom
+
+    assert_equal custom, Gollum::Wiki.default_markup_class
     assert_equal custom, Gollum::Wiki.markup_classes[:orgmode]
-    assert_equal Gollum::MarkupGFM, Gollum::Wiki.markup_classes[:markdown]
+    assert_equal custom_md, Gollum::Wiki.markup_classes[:markdown]
   end
 
   test "repo path" do