Royalty info for existing NFT721 contracts

[fkammer]

The _transferFeesAndFunds method of BaseExchange.sol tries to retrieve the royalty info from the NFT contract. This requires the contract to implement the ERC2981.

shoyu/contracts/base/BaseExchange.sol

Lines 296 to 304 in 3d84540

	try IERC2981(token).royaltyInfo(tokenId, amount) returns (
	address royaltyFeeRecipient,
	uint256 royaltyFeeAmount
	) {
	if (royaltyFeeAmount > 0) {
	remainder -= royaltyFeeAmount;
	_transferRoyaltyFee(currency, royaltyFeeRecipient, royaltyFeeAmount);
	}
	} catch {}

As I understand, for contracts not created via Shoyu and thus probably not having an exchange implemented, ERC721ExchangeV0.sol should act as a more generic version of the exchange allowing to trade allowed NFTs.

Shouldn't we allow existing NFT projects to set a royalty fee if ERC2981 isn't implemented in their existing contract? I'm concerned the marketplace wouldn't be a good fit for a lot of the existing projects otherwise.