v0.7.8

• New cooler cload pairs command provides index-free loading of pairs.
• Changed name of create_from_unsorted to more correct create_from_unordered.

Bug fixes

• Fixed broken use of single-file temporary store in create_from_unordered.
• Added heuristic in pairix cload to prevent excessively large chunks. #92
• Added extra checks in cload pairix and cload tabix. #62, #75