Git 2.1.2

1. 2db1a43 add `ignore_missing_links` mode to revwalk by Vicent Marti · 12 years ago
2. ae4f07f pack-bitmap: implement optional name_hash cache by Vicent Marti · 12 years ago
3. 7cc8f97 pack-objects: implement bitmap writing by Vicent Marti · 12 years ago
4. fff4275 pack-bitmap: add support for bitmap indexes by Vicent Marti · 12 years ago