Based on the original work by Justin Moon.
*MSRV unchanged from 1.29.0.*
When `std` is off, `no-std` must be on, and we use the [`alloc`](https://doc.rust-lang.org/alloc/) and core2 crates. The `alloc` crate requires the user define a global allocator.
* Import from `core` and `alloc` instead of `std`
* `alloc` only used if `no-std` is on
* Create `std` feature
* Create `no-std` feature which adds a core2 dependency to polyfill `std::io` features. This is an experimental feature and should be
used with caution.
* CI runs tests `no-std`
* MSRV for `no-std` is 1.51 or so
This change also moves the secp256k1::Error wrapper from util::Error to
consensus::encode::Error, since we do not use it anywhere else. We can
add it back to util::Error once we have instances of secp256k1::Error
that are not related to consensus::encode.
- Switch util::address::Payload::Pubkey variant to wrap
util:🔑:PublicKey
- Switch util::address::Address::p*k* constructors to use
util:🔑:PublicKey
- Fix tests for aforementioned switch
- Add convenience methods for util:🔑:PublicKey to
util:🔑:PrivateKey conversion
- Switch BIP143 tests to use util:🔑:PublicKey