Fix bug in NULL device resizing; add some more to the vignette, and fix knitr bug in sizing there.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rgl/pkg/rgl@1163 79a1b648-8b68-254f-b20b-c0b50f5137bf
Progress

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rgl/pkg/rgl@1164 79a1b648-8b68-254f-b20b-c0b50f5137bf