SameAs -> From
"internal" GitObject.repo
Simplify signature of ReachableFrom
Reachability: tighten up error handling
Move comment to correct test
Fix if-bracket and empty-enumerable style
Revert "Roll back noisy/pointless changes"

This reverts commit 8a6b156099aaeb185c6de8df20f9eb0f5d58c3be.
Throw when refs can't be backed up
Move RewriteHistory to ReferenceCollection
Clean up usings
Refactor common repo init
Filter-branch: match git's reflog messages