message: added route that appears in the docs
  Reviewers: mark, arik, kevin
  Subscribers: ben
diff: @@ -275,6 +275,14 @@ const handleV2AcceptWalletShare = co(function *(req) {
  return coin.wallets().acceptShare(params);
  });
  +// handle wallet sign transaction
  +const handleV2SignTxWallet = co(function *(req) {
  + const bitgo = req.bitgo;
  + const coin = bitgo.coin(req.params.coin);
  + const wallet = yield coin.wallets().get({ id: req.params.id });
  + return wallet.signTransaction(req.body);
  +});
  +
  // handle sign transaction
  const handleV2SignTx = function(req) {
  const bitgo = req.bitgo;
  @@ -476,6 +484,7 @@ exports = module.exports = function(app, args) {
  app.post('/api/v2/:coin/walletshare/:id/acceptshare', parseBody, prepareBitGo(args), promiseWrapper(handleV2AcceptWalletShare, args));
  // sign transaction
  app.post('/api/v2/:coin/signtx', parseBody, prepareBitGo(args), promiseWrapper(handleV2SignTx, args));
  + app.post('/api/v2/:coin/wallet/:id/signtx', parseBody, prepareBitGo(args), promiseWrapper(handleV2SignTxWallet, args));
  // send transaction
  app.post('/api/v2/:coin/wallet/:id/sendcoins', parseBody, prepareBitGo(args), promiseWrapper(handleV2SendOne, args));
  