i changed the api to not have a global wasm instance anymore. now
initWasm returns a WASM instance you have to pass down to the functions.
i feel like this is the best as it means you wont deal with a race
condition if you're messing with it more then once at the same time,
like i'm doing with tests.
i also accounted for the height given as that was the original
calculation that the Blurhash C implmentation used, not width * width,
width * height.
