Explain the status of the project

Following the discussion golang#1070 (comment)
"Agreed, dep cannot currently be trusted to not make changes after the importers are run.
The issue which tracks that is golang#908.", it is clear that the maintainers of
the tool do not see it as a reliable project.

As such, the users should be correctly informed about the status of the
project and what are the goals in order to make it a production ready one.

README.md

@@ -14,14 +14,14 @@
 
 ## Current status
 
-`dep` is safe for production use. That means two things:
+`dep` has achieved the following milestones:
 
 * Any valid metadata file (`Gopkg.toml` and `Gopkg.lock`) will be readable and considered valid by any future version of `dep`.
-* The CLI UI is mostly stable. `dep init` and `dep ensure` are mostly set; `dep status` is likely to change a fair bit, and `dep prune` is [going to be absorbed into `dep ensure`](https://github.com/golang/dep/issues/944).
-* Generally speaking, it has comparable or fewer bugs than other tools out there.
 
-That said, keep in mind the following:
+The next milestones need to be achieved in order to become safe for production grade usage:
 
+* The CLI UI is mostly stable. `dep init` and `dep ensure` are mostly set; `dep status` is likely to change a fair bit, and `dep prune` is [going to be absorbed into `dep ensure`](https://github.com/golang/dep/issues/944).
+* Generally speaking, it has comparable or fewer bugs than other tools out there.
 * `dep` is still changing rapidly. If you need stability (e.g. for CI), it's best to rely on a released version, not tip.
 * `dep`'s exported API interface will continue to change in unpredictable, backwards-incompatible ways until we tag a v1.0.0 release.