Keep implicit conversion operator() to Attribute[List]
only in the abstract IField and IRecord classes.
Implement them in terms of attribute() and attributeList() methods.

Enclose within #ifdef COOL13 onnly some code in IField and IRecord:
the virtual attribute() and attributeList() methods = 0,
and the operators implemented in terms of them.

Keep in any case the attribute() and attributeList() methods
in all concrete classes.

In summary: if we remove backward compatibility extensions,
we would only touch the abstract base classes IField and IRecord,
which would then become AttributeList-free.
The concrete classes may remain AttributeList-aware in all cases,
since in any case they are defined as wrapper to Attribute[List]s!

2.
Move non-const methods of ConstFieldAdapter to private
(or remove them if their presence is not requested by the base class).


git-svn-id: file:///git/lcgcool.svndb/cool/trunk@7804 4525493e-7705-40b1-a816-d608a930855b