o Added support for expression substitution via regular expressions
  in withCapture().  The default is now to substitute any code matching
  '[.](.+)[.]' with gstring("${\\1}"), e.g. { x <- ".a." } where a <- 1
  becomes { x <- "1" } before being evaluated.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r-dots@2165 edb9625f-4e0d-4859-8d74-9fd3b1da38cb