Moved CircleEntity files to TicTac
Changed App.h to no longer use CircleEntity
Introduced and displayed BoardEntity to TicTac

TicTac/BoardEntity.h
  - Created BoardEntity

TicTac/BoardEntity.cpp
  - Defined constructor and destructor

TicTac/TicTacApp.h
  - Created pointer to BoardEntity

TicTac/TicTacApp.cpp
  - Made app display BoardEntity as white TicTacToe board