Added gui_terminal.py, Minor flip.py changes

flip.py
;    Moved the import statement to its rightful place
;    Made self.string private
;    Added clarification to the purpose of the Data object
gui_terminal.pu
;    Currently gets the game started
;    Asks the user if they'd like music to accompany play
;    Ask the user to write notes or flip tiles
;    Cannot write notes yet
;    Can flip tiles, score is tracked
;    Game Over is possible; asks user if they'd like to play again
;    User cannot "win" game yet