Add log_addins oomhelp function

* src/oomhelp.cpp, src/oomhelp.h (log_addins): New.
(get_oom_object): Debug dispid.

I could not find a place where the call to Item(x) does
not result in the general 80020009 exception. Strange.
There is something fishy here because "Item" has dispid 0. But
this is also what OutlookSpy shows.