some support for call and symbol objects for plotmath

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/lattice@764 3a60a7e4-63ee-4330-9c61-e6b197b972ce
mention simpleTheme() in documentation for 'auto.key'

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/lattice@765 3a60a7e4-63ee-4330-9c61-e6b197b972ce