Don't convert line endings in commit messages.

* Update to include libgit2/libgit2sharp#611
* Revert 4eaabce1ae67eedec8b96a155af4003ef9cff688
* Revise release notes for #534
Reset is only used in one place, to ResetHard.
Use the new form of ObjectDatabase.CreateCommit().
UTC ftw

https://github.com/git-tfs/git-tfs/pull/534#issuecomment-34543386
Update release notes with this PR.
Merge pull request #546 from spraints/lg2s-wip

Better LibGit2Sharp Commits