THE COPY CONSTRUCTOR, ASSIGNMENT OPERATOR AND DESTRUCTOR ARE MISSING!
Merge pull request #1 from linggeli7/patch-1

THE COPY CONSTRUCTOR, ASSIGNMENT OPERATOR AND DESTRUCTOR ARE MISSING!
Update cell.cpp
Merge pull request #2 from linggeli7/patch-2

Update cell.cpp
added world.cpp, updated world.h
Merge pull request #3 from dougyd92/master

add world.cpp
Merge pull request #1 from dcmoyer/master

Doug's Updates