RP-6546 Incorporating Steve Weston's pkgname changes from doSNOW and updating tests and examples. CR by Lixin Gong.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/doparallel@12 edb9625f-4e0d-4859-8d74-9fd3b1da38cb