update albino to 1.2.3, handle bad code blocks gracefully

lib/gollum/albino.rb

@@ -1,30 +1,12 @@
 require 'albino'
 
 class Gollum::Albino < Albino
-  def self.bin
-    Albino.bin
-  end
-
-  def bin
-    Albino.bin
-  end
+  self.bin              = ::Albino.bin
+  self.default_encoding = ::Albino.default_encoding
 
   def colorize(options = {})
     html = super.to_s
     html.sub!(%r{</pre></div>\Z}, "</pre>\n</div>")
     html
   end
-
-  # Hotfix for vulnerable versions of Albino
-  if !instance_methods.include?('shell_escape')
-    def convert_options(options = {})
-      @options.merge(options).inject('') do |string, (flag, value)|
-        string + " -#{flag} #{shell_escape value}"
-      end
-    end
-
-    def shell_escape(str)
-      str.to_s.gsub("'", "\\\\'").gsub(";", '\\;')
-    end
-  end
 end