Problem 396

HI. We've already had two users installing a G4-based platform who encountered
the same
problem: when installing G4, they set G4RADIOACTIVEDATA to point to:
$G4INSTALL/data/G4RadiativeDecay.2.0
In fact, this path was wrong, so that the ion table failed to find the decay
data files and considered all isotopes as stable. Howerver, it did not issue any
warning about it, so that it took quite a while to find out where the problem
was.
Would it be feasible to add a warning for this kind of fairly common mistake? I
guess we don't want warnings popping out each time simulations use stable
isotopes, so you can't just signal whether the isotope data file exists or not,
but couldn't you add a dummy file (such as 'RadiativeDecay.toc') to the
data-file directory? By checking the existence of this file when the decay
process is instanciated, you could fairly easily make sure that the path set in
G4RADIOACTIVEDATA is OK?