message: use createHash(ripemd160) if rmd160 is not supported (e.g. in electron)
diff: var createHash = require('create-hash')
  +var crypto = require('crypto')
  function ripemd160 (buffer) {
  - return createHash('rmd160').update(buffer).digest()
  + var hash = 'rmd160'
  + var supportedHashes = crypto.getHashes()
  + // some environments (electron) only support the long alias
  + if (supportedHashes.indexOf(hash) === -1 && supportedHashes.indexOf('ripemd160') !== -1) {
  + hash = 'ripemd160'
  + }
  +
  + return createHash(hash).update(buffer).digest()
  }
  function sha1 (buffer) {
  