requireNamespace for ipred

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/party@568 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
ipred and vcd functions only via requireNamespace

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/party@569 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
update

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/party@570 edb9625f-4e0d-4859-8d74-9fd3b1da38cb