* Change: In Hurricane::Isobar/PyHurricane.h, make the hash function use
the DBo id whenever possible instead of the object pointer, fall back
to it for standalone objects (Box like one). The DirectHashMethod()
macro generate a C style function (linkage) which call a template
function "getPyHash<>()" that uses a SFINAE mechanism to select
the right variant.
Create two comparison macros DirectCmpByPtrMethod() and
DirectCmpByValueMethod() to customize the comparison for objects that
have C++ operator==(). So now two boxes with the same contents will
be seen equal by Python. For DBo objects we keep the previous
comparison by C++ pointer.