Fix for #4248

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35009 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Fix for #4404

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35010 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
ParseToFunction will work with multivariable too

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35011 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e