Sort static files just once.

Ref: #2075.

lib/jekyll/site.rb

@@ -187,6 +187,7 @@ module Jekyll
       end
 
       pages.sort_by!(&:name)
+      static_files.sort_by!(&:relative_path)
     end
 
     # Read all the files in <source>/<dir>/_posts and create a new Post
@@ -384,7 +385,7 @@ module Jekyll
             "time"         => time,
             "posts"        => posts.sort { |a, b| b <=> a },
             "pages"        => pages,
-            "static_files" => static_files.sort { |a, b| a.relative_path <=> b.relative_path },
+            "static_files" => static_files,
             "html_pages"   => pages.select { |page| page.html? || page.url.end_with?("/") },
             "categories"   => post_attr_hash('categories'),
             "tags"         => post_attr_hash('tags'),

lib/jekyll/static_file.rb

@@ -3,6 +3,8 @@ module Jekyll
     # The cache of last modification times [path] -> mtime.
     @@mtimes = Hash.new
 
+    attr_reader :relative_path
+
     # Initialize a new StaticFile.
     #
     # site - The Site.
@@ -15,6 +17,7 @@ module Jekyll
       @dir  = dir
       @name = name
       @collection = collection
+      @relative_path = File.join(*[@dir, @name].compact)
     end
 
     # Returns source file path.
@@ -22,11 +25,6 @@ module Jekyll
       File.join(*[@base, @dir, @name].compact)
     end
 
-    # Returns the source file path relative to the site source
-    def relative_path
-      @relative_path ||= File.join(*[@dir, @name].compact)
-    end
-
     def extname
       File.extname(path)
     end