fix CRAN warnings, add references, amplify DESCRIPTION


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/soniclength@5 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
fix CRAN warnings, add refs, amplify DESCRIPTION

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/soniclength@6 edb9625f-4e0d-4859-8d74-9fd3b1da38cb