GitLab

closes #2

And indeed we do not want to strip those.

We don't want to pay for a double storage (using the `upstream`
namespace) if we don't use it.

We have to use bits of metadata and introduce an explicit
supervision state: `unsupervised`, `supervised` and `handcrafted`.

`handcrafted` comes from manual=True first insertion. Current
semantics should be reviewed.

Also following tshistory 0.8

auto -> upstream
synth -> edited

We already have what we need.

We replace:
* "automatic" -> "upstream"
* "synthetic" -> "edited"

... as long as the tests use a plain engine to perform write
operations.

This is just a beginning.

Dominant use case is to receive things from excel, which
means the manual edition is actually embedded within
mostly "automatic" data. Very different from a carefully
crafted insert ...

So we'll keep the habit of computing the manual insertions
by diffing automatic against the base (synthetic).