add base64_digest for subresource integrity
missed a spot
provide integrity instead of just the digest.
Merge pull request #645 from mastahyeti/integrity_hash

Add base64_digest for subresource integrity
Note asset integrity
Assert static integrity string
Split digest/hexdigest/base64digest
Switch to SHA256
Compute raw digest bytes instead of hex
Use raw digest for dependency source paths
Store raw byte digest on asset
Generate integrity from existing digest
Prefer hexdigest when possible
Note Asset#digest change
Correct default digest changelog
Build integrity before asset id
Deprecate digest_class in docs
Merge pull request #647 from sstephenson/digest-redux

SHA256 everywhere
fingerprint is always the same as etag
Split off digest utils module