set_indent does not indent tabular environment lines

[jtorcasso]

for instance, you will always have:

    \begin{document}
        \begin{ThreePartTable}
\begin{tabu}{llp{5cm}}

        \textbf{Education} & \textbf{Special Education} & \textbf{\citet{ChambersParrishHarr2004}} \\ 
        \hline