Move links above stats

The first, easy step of #35.
Update to rust master
Handle older entries in the index

Closes #71
Merge branch 'issues/35' of https://github.com/killercup/crates.io into killercup-issues/35
Allow features with '/' in the name

These are just reexported features.

Closes rust-lang/cargo#963
Add API endpoint to retrieve the reverse dependencies.

This /api/v1/crates/foo/reverse_dependencies gives the full dependency
information about each crate that depends on foo (i.e. crates with
`[dependencies] foo = "..."`).
Add the /crate/foo/reverse_dependencies route.

This connects the web-app to the back-end API and allows it to display a
list of all the reverse dependencies of a crate as a
/reverse_dependencies subroute.

This uses the same format as the /versions route.
Add test for rev-dep API endpoint.

This includes making some changes to the test harness, e.g. allowing
dependencies to be added from multiple versions of the dependent crate.
Rewrite the README again

Clarify that UI tweaks don't need to run the API server at all. and streamline
things a bit.
The features map uploaded maps to features!
A handful of cleanups
Fix tidy warnings and add some tests
Merge branch 'wycats-cleanup'
Merge branch 'rev-dep' of https://github.com/huonw/crates.io into huonw-rev-dep
Remove the reverse-dependency model for dependency

Looks like it required a bit of tweaking both server and client side. Also fixes
a link on the reverse dependencies page.
Paginate reverse dependencies
Backend support for paginating reverse dependencies
Handle uploading a pre-0.0.0 version
Require a license, description, and author

This basic set of metadata will now be required for any package to be published.
Cargo will soon support publishing with a `license-file` attribute to override
the license validity check performed here.

cc rust-lang/cargo#940
Specify rev of each buildpack to use