Be able to specify which arguments are defaulted

[kcmerrill]

This is important because sometimes you might not want default all arguments

OR

If we default to a blank string, false, etc etc ... then lets consider it a bunk default value. <-- i like this one better

[kcmerrill]

If the default value is an empty string, or if it's a null value !!null, which defaults to an empty string, then we will spit it out with a missing args error