Add a matrix style to the stylesheet that formats a table to look like a matrix.

Heavily based on the style used by matrepr, but with some tweaks to make it work within the Sphinx/Bootstrap styles.

Usage

Add a

    :class: matrix

directive to any table. This is stackable with other classes, for example :class: inline matrix includes both inline and matrix styles.

If the matrix has row indices, then also add :stub-columns: 1 to mark the leftmost column as a header. This way the leftmost column is styled as indices, but more importantly the matrix border will be in the correct place (i.e. the indices are outside the matrix).

Example:

.. csv-table:: A
    :class: inline matrix
    :header: ,0,1,2,3
    :stub-columns: 1

Effect

Becomes

Closes #496