keep compatibility in the exploration file

[thierry]

PB : Between version .02RC6 and 0.2RC7 there are changes in the format of tne groovy processor. This conduce to a change in the format of the xml file. So a preceding experiment cannot be loaded : this xml file has to be changed manually.

For a user point of view this type of incompatibility is unacceptable. We have to provide some utilities to move to the new format!!!