panicbit

I decided to switch to `hyper` to get rid of the dependency on `curl`, though, it turns out to probably not be worth it. A lot of the Request/Url caching...

I'm not using Windows primarily but AFAIK setting up native dependencies is a pain.

I'm not saying that you shouldn't, but I guess it would be nice to gradually move towards pure Rust crates. Hyper sadly still has a dependency on `openssl`.

We are apparently already doing that, but we're not linking there in the readme https://panicbit.github.io/fcm-rust/fcm/index.html . We should probably add a link to that **and** to docs.rs.