Diff Context Lines (--unified=...)

http://stackoverflow.com/questions/16402124/equivalent-to-git-diff-unified-0-with-libgit2sharp

Currently 3 lines of context is hard-coded: https://github.com/libgit2/libgit2sharp/blob/6a2d99ecdf35288df88c0e6fe8985969042d82a6/LibGit2Sharp/Diff.cs#L27. That should be configurable.