Update libgit2 binaries to 711333e

https://github.com/libgit2/libgit2/compare/11f8336...711333e
Ensure shadow copying doesn't prevent from probing
Introduce RequiresDotNetOrMonoGreaterThanOrEqualTo() helper
Make RetrieveStatus() reload on-disk index beforehand

Fix #322 and #522
Introduce renames in status

Renames in status require more detailed data than simply paths, in
order to collect old path, new path and similarity data.  Use
git_status_list to collect this data and use a new StatusEntry to
store it.