in generateLights, don't call chunkChanged on the neighbors of the requested chunks; just relight them. also slightly improve the progress estimates.
in generateLights, don't call chunkChanged on the neighbors of the requested chunks; just relight them. also slightly improve the progress estimates.

ahh2131/mchisel,arruda/pymclevel,ahh2131/mchisel,codewarrior0/pymclevel,codewarrior0/pymclevel,arruda/pymclevel,mcedit/pymclevel,mcedit/pymclevel