check_box should respond to checked_value / unchecked_value arguments

I noticed that I wasn't able to send in a checked_value / unchecked_value argument for the check_box helper method. I changed the code so that the argument structure corresponds to the default rails check_box form helper method where an optional checked / unchecked value can be supplied **after** the options hash:

`def check_box(object_name, method, options = {}, checked_value = "1", unchecked_value = "0")`