removed printing of sequence after init
added functions to check how many pegs to place
added equality check, added functions for printing feedback pegs
allowed displaying functions to take optional endline string
corrected typo 'differnce' to 'difference'
changed guess method to return the guess as a code object
fixed check_presence method to work correctly
made player guess be validated for length
made player guess be validated for length
provide feedback for invalid guesses