add blocksToReplace to fillBlocks and add tests for fillBlocks
add blocksToReplace to fillBlocks and add tests for fillBlocks

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