cmt-load-env: allow to specify the directory from which to root the cached env.
cmt-save-env: cleanup
pkgco: use logger.Logger. fix g_checkout logic. fix checkout concurrency
pkgco: more logger.Logger usage
pkgco: fix bug in tag/pkg split
pkgco: properly create env. for Gaudi packages' checkout
pkgco: impl. checkout of Gaudi packages
pkgco: implement checkout of atlasoff packages. implement svn_tag_is_trunk
pkgco: cleanup