A smaller version than the original remove ivory-data PR.
Merge pull request #419 from ambiata/topic/undata

A smaller version than the original remove ivory-data PR.
A moderate attempt to remove unsafe/unused code.

This is far from what I would call acceptable, but it is a step
towards containing the differences of repository types again.
It is going to be difficult until s3 is end to end, but we
need to do better at making sure all platforms are supported
on non-mr code for now.
Merge pull request #417 from ambiata/topic/remove-unsafe

A moderate attempt to remove unsafe/unused code.
Removed no-incremental from snapshot.

It was not being followed uniformily, it was causing test code
to follow non-production paths, and was just more useless code.
Added commish to release notes.