changed game.rb attr_accessor attr_reader
refactor contains_digits and contains_letter methods to be more succinct
changed array literal in rover.rb and removed comments on contains_digits/letters methods on game.rb
refactored valid_plateau_input? on plateau.rb
refactored validation logic on rover class
changed all hashes to use symbols instead of strings
updated rover status methods to make it easier to read
added Game class to contain prompt, changed game inputs to a hash, Rover class takes a plateau object
added prompt_user_input logic
added is_going_out_of_bounds? logic and started test
fixed is_going_out_of_bounds? methods and added more test
updated get_plateau_input, get_rover_travel_input, get_rover_input, fixed game.start method to pass Fixnum to Plateau instanciation
fixed test for get_plateau_input, get_rover_input, get_rover_travel_int