Added some interesting methods for the Array object: delete_if{}, delete_first_if{}, delete(obj), delete_first(obj)

Example:

    var abc = [1,2,3,"some",4,"str",5];

    abc.delete_if{|i| i.is_a(String)};
    abc.dump.say;       # prints: [1, 2, 3, 4, 5]