Caching unzipped assets for better performance

[deathcap]

Decompressing the zip on each page load can be slow, consider adding some kind of local caching (localStorage?) to avoid unnecessary zlib deflate

[deathcap]

Also the unnecessary (redundant per load) tile packing and mipmap generation, but that may need to be abstracted into a different module to be cached. Ideally would like to cache almost all of the image data before it is served to the GPU, and only regenerate it if modified (via user customization, e.g. loading a new artwork package).