All relevant uses will rely on the more strict access policy
implemented with the new util::AccessCasted. Along the same line
of thinking, I've removed the "second try" convenience conversion
from the typed get-Function of OpaqueHolder. Such an unbounded
"convert it somehow" approach is almost never a good idea. Either,
one knows by design the precise type to expect, or alternatively
should rely on the base interface solely.
...with the sole exception of the usage in WrapperPointer,
which in itself looks obsolete to me; we should better re-think
the way we handle "wrapped" objects for the BuilderTools, once
we actually start implementing the Builder
Ticket #450
