Make function call arguments match exactly to pass R CMD check.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gradientforest@29 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Avoid over-long lines in manual.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gradientforest@30 edb9625f-4e0d-4859-8d74-9fd3b1da38cb