Fixed rasterEngine and focal_hps so the functions do not need "..." anymore.  Thanks to Ista Zahn for the solution (http://r.789695.n4.nabble.com/Checking-for-and-adding-arguments-to-a-function-tp4685450p4685452.html)

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/spatial-tools@122 edb9625f-4e0d-4859-8d74-9fd3b1da38cb