PChoose = function(list, repeats) {
    Pattern.call(this);
    this.list = list;
    this.repeats = repeats || 1;
    this.position = 0;
}
Choose a random value from an array.

@constructor
@extends Pattern
@param {Object[]} list Array of items to choose from.
@param {Number} [repeats=1] Number of values to generate.