add chunkIsCompressed/Dirty, clean up chunkIsLoaded
add chunkIsCompressed/Dirty, clean up chunkIsLoaded

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