Cherry-pick commits from master to stable-futures (#1296)

* Implement Debug for (ed25519|secp256k1)::(Keypair|SecretKey) (#1285)

* Fix possible arithmetic overflow in libp2p-kad. (#1291)

When the number of active queries exceeds the (internal)
JOBS_MAX_QUERIES limit, which is only supposed to bound
the number of concurrent queries relating to background
jobs, an arithmetic overflow occurs. This is fixed by
using saturating subtraction.

* protocols/plaintext: Add example on how to upgrade with PlainTextConfig1 (#1286)

* [mdns] - Support for long mDNS names (Bug #1232) (#1287)

* Dead code -- commenting out with a note referencing future implementation

* Adding "std" feature so that cargo can build in other directories (notably `misc/mdns`, so that I could run these tests)

* Permitting `PeerID` to be built from an `Identity` multihash

* The length limit for DNS labels is 63 characters, as per RFC1035

* Allocates the vector with capacity for the service name plus additional QNAME encoding bytes

* Added support for encoding/decoding peer IDs with an encoded length greater than 63 characters

* Removing "std" from ring features

Co-Authored-By: Pierre Krieger <pierre.krieger1708@gmail.com>

* Retaining MAX_INLINE_KEY_LENGTH with comment about future usage

* `segment_peer_id` consumes `peer_id` ... plus an early return for IDs that don't need to be segmented

* Fixing logic

* Bump most dependencies (#1268)

* Bump most dependencies

This actually builds 😊.

* Bump all dependencies

Includes the excellent work of @rschulman in #1265.

* Remove use of ed25519-dalek fork

* Monomorphize more dependencies

* Add compatibility hack for rand

Cargo allows a crate to depend on multiple versions of another, but
`cargo-web` panics in that situation.  Use a wrapper crate to work
around the panic.

* Use @tomaka’s idea for using a newer `rand`

instead of my own ugly hack.

* Switch to Parity master

as its dependency-bumping PR has been merged.

* Update some depenendencies again

* Remove unwraps and `#[allow(deprecated)]`.

* Remove spurious changes to dependencies

Bumping minor or patch versions is not needed, and increases likelyhood
of merge conflicts.

* Remove some redundant Cargo.toml changes

* Replace a retry loop with an expect

`ed25519::SecretKey::from_bytes` will never fail for 32-byte inputs.

* Revert changes that don’t belong in this PR

* Remove using void to bypass ICE (#1295)

* Publish 0.13.0 (#1294)

protocols/identify/src/handler.rs

@@ -36,7 +36,6 @@ use libp2p_swarm::{
 use smallvec::SmallVec;
 use std::{marker::PhantomData, pin::Pin, task::Context, task::Poll, time::Duration};
 use wasm_timer::Delay;
-use void::Void;
 
 /// Delay between the moment we connect and the first time we identify.
 const DELAY_TO_FIRST_ID: Duration = Duration::from_millis(500);
@@ -95,7 +94,7 @@ impl<TSubstream> ProtocolsHandler for IdentifyHandler<TSubstream>
 where
     TSubstream: AsyncRead + AsyncWrite + Unpin + 'static,
 {
-    type InEvent = Void;
+    type InEvent = ();
     type OutEvent = IdentifyHandlerEvent<TSubstream>;
     type Error = ReadOneError;
     type Substream = TSubstream;

protocols/identify/src/identify.rs

@@ -36,7 +36,6 @@ use libp2p_swarm::{
     ProtocolsHandlerUpgrErr
 };
 use std::{collections::HashMap, collections::VecDeque, io, pin::Pin, task::Context, task::Poll};
-use void::Void;
 
 /// Network behaviour that automatically identifies nodes periodically, returns information
 /// about them, and answers identify queries from other nodes.
@@ -52,7 +51,7 @@ pub struct Identify<TSubstream> {
     /// Pending replies to send.
     pending_replies: VecDeque<Reply<TSubstream>>,
     /// Pending events to be emitted when polled.
-    events: VecDeque<NetworkBehaviourAction<Void, IdentifyEvent>>,
+    events: VecDeque<NetworkBehaviourAction<(), IdentifyEvent>>,
 }
 
 /// A pending reply to an inbound identification request.