Tokio 1.0

[nightkr]

Fixes #339

Currently uses an unreleased reqwest, since this requires seanmonstar/reqwest#1076

[clux]

Nice work. Looks all fine to me.

Though; since we can't release it until reqwest is released properly, maybe we wait with merging this until #360 is in before merging? @kazk already has a ton of Cargo.toml modifications there, and don't want to make that pr any harder than it already is.

[kazk]

I tried rebasing #360 on top of this. It's doable, but I had to resolve merge conflicts multiple times for Cargo.toml, so merging that first will be cleaner.

To make #360 compile, I had to

• update versions of TLS crates
• update async-tungstenite to v0.11.0
• replace tokio::io::reader_stream() with tokio_util::io::ReaderStream::new() after adding tokio-util = { version = "0.6.0", features = ["io"], optional = true } and including that in ws feature

I'll do a follow-up PR after these two are merged to clean up some things (e.g., using re-exported native-tls and finish rustls support).

[clux]

There's still files marked as conflicting here, I can merge if you want to fix them up.

[nightkr]

Merged latest master now. Something still seems to be borked around tungstenite+rustls though.

[clux]

Well, there were a few follow-up things on that. Tests are at the very least green. I'll merge this one to let people use this as a patch branch.