adjusted NULL for TSrepresentation to be treated as default.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/tsanalysis@181 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Fixed DESCRIPTION titles to title case.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/tsanalysis@182 edb9625f-4e0d-4859-8d74-9fd3b1da38cb