Merge pull request #9 from mglukhovsky/master

Changed the filename parameter for AliasFiles from nil to an empty string.

_plugins/alias_generator.rb

@@ -71,7 +71,7 @@ def generate_aliases(destination_path, aliases)
         end
 
         (alias_index_path.split('/').size + 1).times do |sections|
-          @site.static_files << Jekyll::AliasFile.new(@site, @site.dest, alias_index_path.split('/')[0, sections].join('/'), nil)
+          @site.static_files << Jekyll::AliasFile.new(@site, @site.dest, alias_index_path.split('/')[0, sections].join('/'), '')
         end
       end
     end