Added support for LaTeX style literate Haskell code blocks in rST.
Allow binary 0.5.  Version bump to 1.12.3.1.
Merge pull request #974 from merijn/master

Added support for LaTeX style literate Haskell code blocks in rST.
LaTeX writer: Fix booktabs vertical spacing

- Removed `\addlinespace`. To adjust the vertical space, use `\belowrulesep` and `\aboverulesep` in the template.