Create PredicateX#from(Predicate)

[alexengrig]

Use:

Predicate<Box> predicate = Box::isEmpty; // ok
Predicate<Box> predicate = Box::isEmpty.and(nextPredicate); // not work
Predicate<Box> predicate = PredicateX.from(Box::isEmpty).and(nextPredicate); // work

Implementation:

<T> Predicate<T> from(Predicate<? super T> checker) {
    return (Predicate<T>) checker;
}