Update nitrokey crate to 0.4.0

This change finally updates the version of the nitrokey crate that we
consume to 0.4.0. Along with that we update rand_core, one of its
dependencies, to 0.5.1. Further more we add cfg-if in version 0.1.10 and
getrandom in version 0.1.13, both of which are now new (non-development)
dependencies.

Import subrepo nitrokey/:nitrokey at e81057037e9b4f370b64c0a030a725bc6bdfb870
Import subrepo cfg-if/:cfg-if at 4484a6faf816ff8058088ad857b0c6bb2f4b02b2
Import subrepo getrandom/:getrandom at d661aa7e1b8cc80b47dabe3d2135b3b47d2858af
Import subrepo rand/:rand at d877ed528248b52d947e0484364a4e1ae59ca502

1 files changed, 78 insertions, 0 deletions

diff --git a/getrandom/README.md b/getrandom/README.md
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+# getrandom
+
+[![Build Status](https://travis-ci.org/rust-random/getrandom.svg?branch=master)](https://travis-ci.org/rust-random/getrandom)
+[![Build Status](https://ci.appveyor.com/api/projects/status/github/rust-random/getrandom?svg=true)](https://ci.appveyor.com/project/rust-random/getrandom)
+[![Crate](https://img.shields.io/crates/v/getrandom.svg)](https://crates.io/crates/getrandom)
+[![Documentation](https://docs.rs/getrandom/badge.svg)](https://docs.rs/getrandom)
+[![Dependency status](https://deps.rs/repo/github/rust-random/getrandom/status.svg)](https://deps.rs/repo/github/rust-random/getrandom)
+
+
+A Rust library for retrieving random data from (operating) system source. It is
+assumed that system always provides high-quality cryptographically secure random
+data, ideally backed by hardware entropy sources. This crate derives its name
+from Linux's `getrandom` function, but is cross platform, roughly supporting
+the same set of platforms as Rust's `std` lib.
+
+This is a low-level API. Most users should prefer using high-level random-number
+library like [`rand`].
+
+[`rand`]: https://crates.io/crates/rand
+
+## Usage
+
+Add this to your `Cargo.toml`:
+
+```toml
+[dependencies]
+getrandom = "0.1"
+```
+
+Then invoke the `getrandom` function:
+
+```rust
+fn get_random_buf() -> Result<[u8; 32], getrandom::Error> {
+    let mut buf = [0u8; 32];
+    getrandom::getrandom(&mut buf)?;
+    Ok(buf)
+}
+```
+
+## Features
+
+This library is `no_std` for every supported target. However, getting randomness
+usually requires calling some external system API. This means most platforms
+will require linking against system libraries (i.e. `libc` for Unix,
+`Advapi32.dll` for Windows, Security framework on iOS, etc...).
+
+The `log` library is supported as an optional dependency. If enabled, error
+reporting will be improved on some platforms.
+
+For the `wasm32-unknown-unknown` target, one of the following features should be
+enabled:
+
+-   [`wasm-bindgen`](https://crates.io/crates/wasm_bindgen)
+-   [`stdweb`](https://crates.io/crates/stdweb)
+
+By default, compiling `getrandom` for an unsupported target will result in
+a compilation error. If you want to build an application which uses `getrandom`
+for such target, you can either:
+- Use [`[replace]`][replace] or [`[patch]`][patch] section in your `Cargo.toml`
+to switch to a custom implementation with a support of your target.
+- Enable the `dummy` feature to have getrandom use an implementation that always
+fails at run-time on unsupported targets.
+
+[replace]: https://doc.rust-lang.org/cargo/reference/manifest.html#the-replace-section
+[patch]: https://doc.rust-lang.org/cargo/reference/manifest.html#the-patch-section
+
+## Minimum Supported Rust Version
+
+This crate requires Rust 1.32.0 or later.
+
+# License
+
+The `getrandom` library is distributed under either of
+
+ * [Apache License, Version 2.0](LICENSE-APACHE)
+ * [MIT license](LICENSE-MIT)
+
+at your option.