[Docutils-develop] Patch for equations, theorems, and figures in LaTeX

[Alex <al...@gm...>]

Hello,

I've recently been working on a project in which a few extensions to the
rST format have proven to be quite useful. Now that I've finished my
patch and (informally) tested it, I thought I might share it with the
developers in case it would be useful, perhaps even integrated in time.

The following features have been added:
 * Labelling for figures via the `label` option under the `figure`
directive.
 * Referencing for figures via the `fig` role, for latex2e writer.
 * Labelling for equations via the `label` option under the `equation`
directive.
 * Referencing for figures via the `eq` role, for latex2e writer. Uses
amsmath `eqref` macro.
 * Created `theorem` directive; supports theorem-style (i.e. theorem,
definition, proof) blocks in latex2e. Includes options for setting
`title` and `label`.
 * Referencing for theorems via the `th` role, for latex2e writer.

I've tried to follow the guidelines where appropiate - though the code
in some places may be slightly messier (than ideal). I've filled in the
language files, mainly with (translation required) for all except en.

The SVN diff patch from r6486 is attached. I hope it can be of some use.

Regards,
Alex