Fix Query(params IPredicate[] predicates)

[AlexFursenkoOd]

Could you modify method Query(params IPredicate[] predicates) in Form.cs to use iterator of type IPredicate instead of Predicate. Until you do so there is no way to create my own predicate. There is no sense to inherit from IPredicate because method Query uses iterator of type Predicate, so if I pass my predicate of type IPredicate method will try to convert it to instance of type Predicate which will through an Exception.

Or perhaps mark method Query of type Predicate as virtual. This way we can inherit from type Predicate. It will allow us to override existing implementation of Predicate class
Anyway, for now there is no real way to add not supported in this library predicates (like "has")