move to the new uproxy-lib world

This moves the repo to the new `uproxy-lib` world (4.x.x).

Summary:
* add per-module typescript definitions
* move samples under the modules-under-test
* add a `tsd/` tree
* update imports

This also kills the `copypaste` sample. I was planning to do that in my next merge but since it's a bit of work to migrate to the new build system, I opted to do it now. Also, you might point out that while the `chat` sample is under `pipe`, it doesn't actually use `pipe`. Well, my next pull request will make that clearer :-)