Memory leak

[kf106]

I think there is a memory leak in the implementation. The following simple short program consumes an extra 150Mb of memory every second that is not released:

const keccak256 = require('keccak256');

for (let i = 0; i < 100000000000; i++) {
    const result = keccak256('something');
}

[Krisseck]

Did some testing, I think the issue is in keccak package, not this package. Didn't see any issues raised in the repo though.

If it helps, I have been using keccak256 from js-sha3, that one has no memory leaks

https://github.com/emn178/js-sha3