message: Break out encrypt and decrypt Web Crypto usage options.
diff: var WebCryptoUsage = module.exports = {
  /** encrypt/decrypt */
  ENCRYPT_DECRYPT: [ 'encrypt', 'decrypt' ],
  + /** encrypt */
  + ENCRYPT: [ 'encrypt' ],
  + /** decrypt */
  + DECRYPT: [ 'decrypt' ],
  /** wrap/unwrap */
  WRAP_UNWRAP: [ 'wrap', 'unwrap' ],
  /** wrap */
  