This has the following nice benefits:
* The 'Uuid' wrapper type is gone.
* 'Uuid' implements 'UriDisplay', 'FromUriParam'.
* The 'serialization' example merges in 'uuid'.
Resolves#1299.
The new examples directory...
* Contains a `README.md` explaining each example.
* Consolidates examples into more complete chunks.
* Is just better.
Resolves#1447.
This allows us to test all of the "core" crates (and the guide) by
testing the root workspace, and all of the examples by testing in the
examples workspace.
Sergio Benitez