Storage: Modified, unsaved chunks are stored on disk instead of being retained in memory.
Storage: Modified, unsaved chunks are stored on disk instead of being retained in memory.

This allows potentially unlimited numbers of chunks to be modified in a single session.

mcedit/pymclevel,arruda/pymclevel,ahh2131/mchisel,ahh2131/mchisel,arruda/pymclevel,mcedit/pymclevel