We have contexts.hash_id which is enough (computed by postgres as a
trigger).

Merge remote-tracking branch 'origin/314-node-phylo-change-the-default-value-of-findancestors-to-false' into dev

Test failed, not merging.

This reverts commit 2e77bfa5, reversing
changes made to fe201115.

This commit switch the PhyloMaker.hs code to use, whenever we can,
faster implementations for nub and sort.

It also adds a semi-interesting phylo.