particle collision fixes


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1585 b412e182-2ed4-4078-95c4-27dc59f57fa9
make texture browser use slots


git-svn-id: svn://svn.tuxfamily.org/svnroot/tesseract/main@1586 b412e182-2ed4-4078-95c4-27dc59f57fa9