all as.Date() methods were fully exported
now additionally registered as S3method()



git-svn-id: svn://svn.r-forge.r-project.org/svnroot/zoo@1015 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
reverted col.names change in ggplot2 tools as well because the examples failed to check

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/zoo@1016 edb9625f-4e0d-4859-8d74-9fd3b1da38cb