started module for computing significance with random permutation/effect size
correction bug astar + tests
Merge pull request #2 from phimit/master

correction astar bug
Introduce a vaguely CONLL shaped output

The hope is that this would be

1. more compact (single edu instead of pairs, so less redundancy)
2. more recognisable to people from parsing communities
3. more standard(ish)

But note the awkwardness around the output being more a graph
than a tree
Try to document our CONLL style format a bit