- Replace calls to missing(x) with !hasArg(x) in order to avoid errors
  in getSymbols "methods" that do not have 'x' as a formal argument.


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/quantmod@623 edb9625f-4e0d-4859-8d74-9fd3b1da38cb