message: Return algo keyreg data from explainTransaction
  This commit returns type, senderAddress, voteKeyBase64, and
  voteLastBlock from explainTransaction. The OVC needs this data to verify
  what it is signing.
  JIRA:
diff: @@ -35,6 +35,10 @@ const co = Bluebird.coroutine;
  export interface TransactionExplanation extends TransactionExplanation {
  memo: string;
  + type?: string;
  + senderAddress?: string;
  + voteKeyBase64?: string;
  + voteLastBlock?: number;
  }
  export interface SignTransactionOptions {
  @@ -219,7 +223,7 @@ export class Algo extends BaseCoin {
  if (!txHex) {
  throw new Error('missing required param txHex or halfSigned.txHex');
  }
  - let tx;
  + let tx, type, senderAddress, voteKeyBase64, voteLastBlock;
  try {
  const txToHex = Buffer.from(txHex, 'base64');
  const decodedTx = Encoding.decode(txToHex);
  @@ -228,6 +232,12 @@ export class Algo extends BaseCoin {
  // if we are not signed, the decoded tx is the txn - refer to partialSignTxn and MultiSig constructor
  // in algosdk for more information
  const txnForDecoding = decodedTx.txn || decodedTx;
  + if (!!txnForDecoding.votekey) {
  + type = txnForDecoding.type;
  + senderAddress = Address.encode(txnForDecoding.snd);
  + voteKeyBase64 = txnForDecoding.votekey.toString('base64');
  + voteLastBlock = txnForDecoding.votelst;
  + }
  tx = Multisig.MultiSigTransaction.from_obj_for_encoding(txnForDecoding);
  } catch (ex) {
  @@ -250,7 +260,19 @@ export class Algo extends BaseCoin {
  const memo = tx.note;
  return {
  - displayOrder: ['id', 'outputAmount', 'changeAmount', 'outputs', 'changeOutputs', 'fee', 'memo'],
  + displayOrder: [
  + 'id',
  + 'outputAmount',
  + 'changeAmount',
  + 'outputs',
  + 'changeOutputs',
  + 'fee',
  + 'memo',
  + 'type',
  + 'senderAddress',
  + 'voteKeyBase64',
  + 'voteLastBlock',
  + ],
  id,
  outputs,
  outputAmount,
  @@ -258,6 +280,10 @@ export class Algo extends BaseCoin {
  fee,
  changeOutputs: [],
  memo,
  + type,
  + senderAddress,
  + voteKeyBase64,
  + voteLastBlock,
  };
  })
  .call(this)
  