Support inherited classes in Mappers.

Mappers support only POJOs that extend the Object class.
It looks possible to map more complex objects to the table columns.

E.g. class B in the code example below, could be mapped to the schema with columns

However, parent fields could be hidden in descendants (see class C in the example below). The default behavior in the case should be failing.
One could use annotations to map hidden fields to a different column,
but there should be a way to express this programmatically with a mapper (without annotations).

class A {
    int f1;
}

class B extends A {
    long f2
}

class C extends A {
   int f1; // Hides field A.f1
}