Fix deleteByFk method

[chous]

The delete method of RDB implementations of the DAOs tries to delete all entities depending on it. In other words, it simplifies the deletion on cascade of a graph of dependant entities.

Currently, such logic is commented out in the templates, since it contains errors. The purpose of this ticket is, obviously, to fix such errors.

[chous]

The foreign keys the DAO template is aware of seem ok, but the code always use source table information instead of referring tables. As an example, A -> B <- C

BDAO.delete(bpk) {
  bdao.deleteByBPk(bpk); // should be adao.deleteByBpk(bpk);
  bdao.deleteByBPK(bpk); // should be cdao.deleteByBpk(bpk);
  // delete B by bpk...
}