improve dereferencing

Dereferencing for fields not eding with ID will
append _text now

$this->hasOne('User','created_by');

creates 2 fields - 'created_by' and 'created_by_txt'. It used
to have created_by_2 or some other number at the end.
non-initialized fields in non-loaded models are now null.

Use strict mode if you want extra control