Work with typemap

[duelinmarkers]

Here's a way of making iron/persistent work with the recent change to use typemap for request extensions. I don't know if you already have something else in mind.

It requires the phantom key type to impl Assoc<Arc<RWLock<D>>>, which is a bit ugly, but only makes explicit dependencies that were already there.

[reem]

Thanks! Can you add rust-typemap to the Cargo.toml here, this works because Iron depends on it so it ends up in /target/deps, but I'd rather the dependency was made explicit.

This crate needs to be reworked pretty significantly, but it's good to have it build again for now.

[duelinmarkers]

There you go.