new (failing) test for Data.FormValidator dependencies

[Mark Stosberg]

The current implementation of dependencies does not cover the case of
creating the dependency based on whether a particular value is present
for a field. Perl's DFV does this with a syntax like this:

dependencies : {

pay_type : {
Check : ['cc_num'],

}
}

I've written a test to confirm this is unimplemented here:

http://mark.stosberg.com/javascript/dfv-dependency.t.html

However, it seems my JavaScript-fu is still too weak to actually add
this functionality at this point.

Mark