added new test-class for OObjectEnumLazyList

included test-cases:
  - containsTest()
  - indexOfTest()
  - lastIndexTest()
  
refactored methods in OObjectEnumLazyList

- contains(Object o)
- indexOf(Object o)
- lastIndexOf(Object o)

All methods are including the same problem. There are two lists:
List<Object> and ArrayList<Type>. List<Object> contains String values
and is equals to the String values in the database. The Strings
represent the names of the enum-values. The ArrayList<Type> contains the
real enum-values, but these values are only loaded when the method
get(int index) will be used, otherwise the list only contains
null-values. So indexOf and contains doesn't work with this list.
So, if Object is a valid enum for this list, the name of this enum-value
will be used to use contains/indexOf of the List<Object> list.