NOTES

o Functions or methods starting with '_' are internal to osperl.  They
should not be used and are subject to change without notice.

o Dependencies are not properly tracked by Maker.  You should remove
all object files if you suspect they are out of sync.

o Avoid const, private & templates.  C++ sucks.  Long live C++!

o The following might change the perl stack:
  OSSVPV::_bless,
  OSSVPV::_blessed_to, wrap_object, osp::*_2sv, osp::push_*
  osperl::force_sv_2bridge, OSSV::operator=

o Weak references are conceptually orthogonal to cursors.  However,
the extra complexity necessary to split the dimension seems like
overkill.  After more contemplation, maybe they are not orthogonal.
In any case, it is far simpler just to make cursors a subclass of
references.

o Cross database pointers cannot be enabled.  They are too dangerous
for reference counted data.

o Coding XS is very strange.
