New Features
- Add method argument to glmtree. The default is to use "glm.fit"
(as was hard-coded previously) but this can also be changed,
e.g., to "brglmFit" from brglm2 for bias-reduced estimation of
generalized linear models.
Bugfixes
- Fix LaTeX problem.
- Better checks for response classes, fixing a bug reported by
John Ogawa.
- In lmtree and glmtree the "xlevels" attribute for the
regressors is preserved in the models fitted within the trees.
Thus, predicting for data whose "xlevels" do not match, an
error is generated now (as opposed to warning and partially
incorrect predictions).
