Added .gitignore

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r-dots@2163 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Ignoring more files

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r-dots@2164 edb9625f-4e0d-4859-8d74-9fd3b1da38cb