radicle-git init

Port over all git relevant parts of the radicle-link repository[0].
The packages that are kept are:
* git-ext
* git-ref-format
* git-trailers
* link-git
* macros
* std-ext
* test -- only the portions that test the above

The development and testing scripts are also added for local and CI
testing.

[0]: https://github.com/radicle-dev/radicle-link/
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>

git-ext/src/reference.rs

@@ -0,0 +1,26 @@
+// Copyright © 2019-2020 The Radicle Foundation <hello@radicle.foundation>
+//
+// This file is part of radicle-link, distributed under the GPLv3 with Radicle
+// Linking Exception. For full terms see the included LICENSE file.
+
+use std::convert::TryFrom as _;
+
+mod iter;
+pub use iter::{ReferenceNames, References};
+
+pub mod name;
+pub use name::{OneLevel, Qualified, RefLike, RefspecPattern};
+
+pub mod check {
+    pub use git_ref_format::{check_ref_format as ref_format, Error, Options};
+}
+
+pub fn peeled(head: git2::Reference) -> Option<(String, git2::Oid)> {
+    head.name()
+        .and_then(|name| head.target().map(|target| (name.to_owned(), target)))
+}
+
+pub fn refined((name, oid): (&str, git2::Oid)) -> Result<(OneLevel, crate::Oid), name::Error> {
+    let name = RefLike::try_from(name)?;
+    Ok((OneLevel::from(name), oid.into()))
+}