Added Dice.php - defines a 'Dice' class which represents a (group of) gaming dice with an arbitrary number of sides and an optional bonus/penalty. The dice can be 'rolled' to generate random numbers, and the results of a 'roll' can be easily examined as a total (with or without the bonus/penalty) or as an array of individual results (one int from 1-$sides per dice in the group).
Can either be constructed by number/sides/bonus (all optional, defaulting to 1/6/0) or parsed from a human-readable string (e.g. '2d6+2'), and convert to the same format when printed as a string.