Optimised ERC721 implemention

Based on Citizens of Tajigen's implementation.

Our personal tests showed the above contract to be superior among all the implementations we were aware of: https://twitter.com/AlgorithmicBot/status/1552722851345702913

Dev

To generate coverage report run

forge coverage --report lcov && genhtml lcov.info -o report --branch-coverage

To run the tests run

forge test

There is also an argument for different levels of verbosity:

forge test -v

All the way up to -vvvvv

Goerli Test Deploy

Rumble Kong League OG stub collection deployed at: 0xfC01aE2764Ca9CD8ABbf10aBf430Ca4661AEAcd9. You can arbitrarily mint kongs with the following function mint(address to, uint256 qty).

Test Rookies Claim contract was deployed to: 0xaBb95Abfb3D79DAF27558E5Aff8bf714922bA8dB.