|Author||Jackson Chan, Clinton Ennis|
Upgrade type of currencyKeys from Bytes4 to Bytes32.
Synthetix wants to create new synths with symbols longer than 4 chars. i.e sATOM, sDEFI This is currently not possible with currencyKeys type defined as Bytes4.
The system was originally built with currencyKeys as Bytes4 to save storage space. However the system requirements have changed to require Symbols longer than 4 charactors for Synths like the DeFI index token sDEFI.
Change all instances of Bytes4 to Bytes32 in Synth.sol and Synthetix.sol.
Copyright and related rights waived via CC0.