Adjusted calls of *.fit() to *model() and worth() to itempar().

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/prefmod@234 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Updated NAMESPACE to new itempar methods.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/prefmod@235 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Fixed several bugs in graphical functions.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/prefmod@236 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Updated psychotree-Ex.Rout.save and removed in from .Rbuildignore.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/prefmod@237 edb9625f-4e0d-4859-8d74-9fd3b1da38cb