Nix fs.async.* methods. They aren't needed now.

native/v8_extensions/native.js

@@ -25,9 +25,6 @@ var $native = {};
   native function remove(path);
   $native.remove = remove;
 
-  native function asyncList(path, recursive, callback);
-  $native.asyncList = asyncList;
-
   native function open(path);
   $native.open = open;
 

native/v8_extensions/native.mm

@@ -159,9 +159,6 @@ bool Native::Execute(const CefString& name,
 
     return true;
   }
-  else if (name == "asyncList") {
-    return false;
-  }
   else if (name == "writeToPasteboard") {
     NSString *text = stringFromCefV8Value(arguments[0]);