Correct NULL condition handling.
Correct variable name mistake.
Use an associative field array instead of two indexed arrays.
Allow user not to set array for HasMany and ManyMany relations.
Avoid array accesses in LM cascade saves.
Add access to PDO beginTransaction() and rollBack() functions.
Convert DateTime to string before save into DB.
Throw MalformedOptionException when order_by attribute is empty.
Correct conversion into DateTime at object initialization.

- Check if corresponding option is set to true once instead doing it at every
  loop.
- Do not transform NULL-like values.
- Assure that the value is a string before converting.
Throw Database Exceptions instead of overlaying them.
Correct namespaces when throw Exceptions.

Add \SimpleAR\ prefix.
Add "has" option for Count queries.
Add has() method.