INSUFFICIENT_TAKER_ALLOWANCE when taker is open order book

[coopermaruyama]

This test was done on Kovan.

When using the open order book, filling an order causes an INSUFFICIENT_TAKER_ALLOWANCE error to be thrown by the exchange simulator. It's thrown on this line: https://github.com/0xProject/0x.js/blob/development/src/utils/exchange_transfer_simulator.ts#L100

I think this is because getAllowanceAsync using the address of the open order book's allowance returns 0 for any spender.

[coopermaruyama]

I've solved this by doing the following when creating the initial order:

await zeroEx.token.setUnlimitedAllowanceAsync(
  takerTokenAddress, 
  makerAddress,
 '0x0000000000000000000000000000000000000000'
);

If I'm doing this wrong let me know please!