* Change: In Hurricane::SharedPath, the hash for the shared pathes, which
serves for Map<> storing, were computed "on the fly" at each
::getHash() call, and were involving recursive calls of all the
hashes along the components of the shared path. This is terribly
slow especially in a design with a deep hierarchy (typical case
LS180).
Now, at the cost of one supplemenental unsigned long in each
SharedPath, it is only computed once in the constructor, and is
no longer recursive (only access the *first* tail, if any).
As a consequence, the re-display computation delay becomes
bearable. But also speed up any transhierarchical walkthough.