Version 1.1.0

Added

• Implement Iterator and IntoIterator for MerkleTree (@romac)

Changed

• Avoid allocating memory on the heap in HashUtils, and made combine_hashes more efficient (@briansmith)
• Bump ring to ^0.6.0 and protobuf to ^1.2.0 (@romac)

Initial release.

Initial release of merkle.rs.