precis-0.3.1

Copperbox revision 1292.

I've made a new release of precis - 0.3.1. I actually made a release at 0.3.0 by svn had a commit problem and while reported a failure while the commit seemingly worked, so I've bumped the version number and remade the binary.

Version 0.3.X added type signature and data declaration diffs.

Copperbox revision 1291 - commit failed on this one, so I consider precis-0.3.0 invalid