Update for recent chainhash-related API changes.

[davecgh]

This PR requires btcsuite/btcd#729.

This updates all code in the main package and subpackages to make use of the new chainhash package since the old wire.ShaHash type and functions have been removed in favor of the abstracted package.

Also, since this required API changes anyways and the hash algorithm is no longer tied specifically to SHA, all other functions throughout the code base which had Sha in their name have been changed to Hash so they are not incorrectly implying the hash algorithm.

The following is an overview of the changes:

• Update all references to wire.ShaHash to the new chainhash.Hash type
• Rename the following functions and update all references:
  • Block.Sha -> Hash
  • Block.TxSha -> TxHash
  • Tx.Sha -> Hash
  • bloom.Filter.AddShaHash -> AddHash
• Rename all variables that included sha in their name to include hash instead
• Add license headers to coinset package files

NOTE: This PR will fail the CI build because it depends on the aforementioned btcd PR.

[jcvernaleo]

OK

[marcopeereboom]

ok

[cjepson]

OK