Fix link to crates.io

* Remove all usage of `mem::uninitialized()`

Backport from [upstream](https://github.com/rust-bitcoin/rust-secp256k1/pull/146)

Closes #23

* Remove deprecated functions

ordian authored Oct 23, 2019 and David committed Oct 23, 2019

Fixes #28

Update readme

Use the correct name: `parity-secp256k1`. Document that there's a submodule involved.

Remove keyword for publishing

Publish crate to crates.io

Upgrade dependencies and use a Git submodule for libsecp256k1

[Cargo.toml] update rand to 0.7 (breaking change)

Also add Parity as an author.

ci: add .gitlab-ci.yml

* master:
  Update src/ffi.rs
  s/EcdhHashFunction/EcdhHashFn
  revert unrelated change
  refactor ecdh_raw
  fix ecdh ffi
  fix rand tests
  remove schnorr support

fix ecdh ffi

Co-Authored-By: David <[email protected]>

update c-lib to upstream