message: add Transaction class, remove RejectedRegistrant
diff: class Registrant {
  -
  constructor( eth, eos = "", balance = 0 ){
  // let {unclaimed, wallet, recovered} = balances
  this.eth = eth
  this.eos = eos
  this.balance = typeof balance == 'object' ? balance : new Balance()
  + this.accepted = null
  + this.error = false
  + }
  +
  + accept ( callback ) {
  + this.accepted = true
  }
  - set( key, value ){
  - this[ key ] = value;
  + reject ( error ) {
  + if(!error) return;
  + this.error = error
  + this.accepted = false
  }
  + is_accepted () {
  + return this.accepted === true
  + }
  +
  +}
  +
  +class Transaction {
  +
  + constructor( eth, tx, type = "transfer", amount ) {
  + this.eth = eth
  + this.hash = tx
  + this.amount = amount
  + this.claimed = false
  + this.type = type
  + }
  +
  + claim( eth ) {
  + return ( eth == this.eth )
  + ? this.claimed = true
  + : log("error", `${eth} should't be claiming ${this.eth}'s transaction`)
  + }
  }
  @@ -36,7 +64,7 @@ class Balance {
  this.total = web3.toBigNumber(0)
  }
  - update( type, balance ){
  + set( type, balance ){
  this[ type ] = balance
  return this //chaining
  }
  