\cdbproperty{TableauSymmetry}{\it shape={\sf tableau shape},
indices={\sf index positions}, selfdual, antiselfdual}

Takes lists of two key-value pairs as arguments, indicating the 
shape of the Young tableau and the index slots associated to each box
in the tableau. For instance
\begin{screen}{1}
R_{a b c d}::TableauSymmetry( shape={2,2}, indices={0,2,1,3} ).
\end{screen}
yields the symmetries of the Riemann tensor. Note that indices are
counted from zero. It is also possible to label tensors as self-dual
or anti-selfdual using the optional arguments.
