very minor improvement of risk.measure and comments

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/qrm@81 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
added warning to gamGPDfit() in case gam() fails and thus list() is returned

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/qrm@82 edb9625f-4e0d-4859-8d74-9fd3b1da38cb