Feature request: Support double lines in tables

Created by: celtschk

Consider the following code, creating a filled Sudoku field with LaTeX:

\begin{array}{||c|c|c||c|c|c||c|c|c||}
\hline\hline
1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 \\
\hline
4 & 5 & 6 & 7 & 8 & 9 & 1 & 2 & 3 \\
\hline
7 & 8 & 9 & 1 & 2 & 3 & 4 & 5 & 6 \\
\hline\hline
2 & 3 & 1 & 5 & 6 & 4 & 8 & 9 & 7 \\
\hline
5 & 6 & 4 & 8 & 9 & 7 & 2 & 3 & 1 \\
\hline
8 & 9 & 7 & 2 & 3 & 1 & 5 & 6 & 4 \\
\hline\hline
3 & 1 & 2 & 6 & 4 & 5 & 9 & 7 & 8 \\
\hline
6 & 4 & 5 & 9 & 7 & 8 & 3 & 1 & 2 \\
\hline
9 & 7 & 8 & 3 & 1 & 2 & 6 & 4 & 5 \\
\hline\hline
\end{array}

In LaTeX, this generates a field with double-lines separating the Sudoku sub-squares. In MathJax, this doesn't work.

My feature request now is to make it work with MathJax. Note that an exact replication of the LaTeX output is not required (indeed, the LaTeX output itself leaves room for improvement). The important part is that the double lines (marked by || for vertical lines, and \hline\hline for horizontal lines) are visibly different from the single lines.