Model and controller

@bsoetaer 
Test by opening irb and creating a new CLIClient.  Use start and quit to start a new game or exit the program, and select a column to play by entering the zero-based column number.
Will we be able to have multiple games started with this design? @@game means it is for all uses of the module correct? not just one instance? 
Note: not too much to do with this assignment but thinking of project 5.