Pygit2

Breaking changes:

- Now `discover_repository` returns `None` if repository not found,
instead of raising `KeyError`
[531](https://github.com/libgit2/pygit2/issues/531)

Other changes:

- New `DiffLine.raw_content`
[610](https://github.com/libgit2/pygit2/issues/610)
- Fix tests failing in some cases
[795](https://github.com/libgit2/pygit2/issues/795)
- Automatize wheels upload to pypi
[563](https://github.com/libgit2/pygit2/issues/563)

- Update to libgit2 v0.27
[783](https://github.com/libgit2/pygit2/pull/783)
- Fix for GCC 4 [786](https://github.com/libgit2/pygit2/pull/786)

Backward incompatible changes:

- Now iterating over a configuration returns `ConfigEntry` objects
[778](https://github.com/libgit2/pygit2/pull/778)

Before
for name in config:
value = config[name]

Now
for entry in config:
name = entry.name
value = entry.value

Other changes:

- Added support for worktrees
[779](https://github.com/libgit2/pygit2/pull/779)
- New `Commit.gpg_signature`
[766](https://github.com/libgit2/pygit2/pull/766)
- New static `Diff.parse_diff(...)`
[774](https://github.com/libgit2/pygit2/pull/774)
- New optional argument `callbacks` in
`Repository.update_submodules(...)`
[763](https://github.com/libgit2/pygit2/pull/763)
- New `KeypairFromMemory` credentials
[771](https://github.com/libgit2/pygit2/pull/771)
- Add missing status constants
[781](https://github.com/libgit2/pygit2/issues/781)
- Fix segfault [775](https://github.com/libgit2/pygit2/issues/775)
- Fix some unicode decode errors with Python 2
[767](https://github.com/libgit2/pygit2/pull/767)
[768](https://github.com/libgit2/pygit2/pull/768)
- Documentation improvements
[721](https://github.com/libgit2/pygit2/pull/721)
[769](https://github.com/libgit2/pygit2/pull/769)
[770](https://github.com/libgit2/pygit2/pull/770)

- New `Diff.deltas`
[736](https://github.com/libgit2/pygit2/issues/736)
- Improvements to `Patch.create_from`
[753](https://github.com/libgit2/pygit2/pull/753)
[756](https://github.com/libgit2/pygit2/pull/756)
[759](https://github.com/libgit2/pygit2/pull/759)
- Fix build and tests in Windows, broken in the previous release
[749](https://github.com/libgit2/pygit2/pull/749)
[751](https://github.com/libgit2/pygit2/pull/751)
- Review `Patch.patch`
[757](https://github.com/libgit2/pygit2/issues/757)
- Workaround bug
[4442](https://github.com/libgit2/libgit2/issues/4442) in libgit2,
and improve unit tests
[748](https://github.com/libgit2/pygit2/issues/748)
[754](https://github.com/libgit2/pygit2/issues/754)
[758](https://github.com/libgit2/pygit2/pull/758)
[761](https://github.com/libgit2/pygit2/pull/761)

- New property `Patch.patch`
[739](https://github.com/libgit2/pygit2/issues/739)
[741](https://github.com/libgit2/pygit2/pull/741)
- New static method `Patch.create_from`
[742](https://github.com/libgit2/pygit2/issues/742)
[744](https://github.com/libgit2/pygit2/pull/744)
- New parameter `prune` in `Remote.fetch`
[743](https://github.com/libgit2/pygit2/pull/743)
- Tests: skip tests that require network when there is not
[737](https://github.com/libgit2/pygit2/issues/737)
- Tests: other improvements
[740](https://github.com/libgit2/pygit2/pull/740)
- Documentation improvements

- New `Repository.free()`
[730](https://github.com/libgit2/pygit2/pull/730)
- Improve credentials handling for ssh cloning
[718](https://github.com/libgit2/pygit2/pull/718)
- Documentation improvements
[714](https://github.com/libgit2/pygit2/pull/714)
[715](https://github.com/libgit2/pygit2/pull/715)
[728](https://github.com/libgit2/pygit2/pull/728)
[733](https://github.com/libgit2/pygit2/pull/733)
[734](https://github.com/libgit2/pygit2/pull/734)
[735](https://github.com/libgit2/pygit2/pull/735)