Swap.check does not account for null sender.wallet values (i.e. public order)

[don mosites]

I.e. when:

{ "sender": { "wallet": "0x0000000000000000000000000000000000000000", ... }, ... }

check should verify similar to swap:
https://github.com/airswap/airswap-protocols/blob/develop/source/swap/contracts/Swap.sol#L98
which would also require an address senderWallet argument passed to the check function.