Auto merge of #2621 - jtgeibel:hyper-as-default, r=JohnTitor
Auto merge of #2621 - jtgeibel:hyper-as-default, r=JohnTitor

Switch to hyper as the default web server

This is changed so that running `cargo run --bin server` locally uses
the same web server that we are running in production. The `civet`
server can be selected by setting the `WEB_USE_CIVET` environment
variable to any value (including an empty string).

r? @JohnTitor
cc #2204

rust-lang/crates.io,rust-lang/crates.io,rust-lang/crates.io,rust-lang/crates.io