Officially disable the copy c'tor of SdrObject.

Change-Id: I5f4ccad5077427afd09668c93f56c0ecce5f6f5d
Add Impl to SdrObject and hide ObjectUser member.

SdrObject is quite large and we can't pimplize it in one go.  Let's do
it bit by bit.

Change-Id: I40abe71799f6dcae90854dcc6979acc1d6ed7462
Move these to Impl and remove boost::optional include.

Change-Id: I394d164c4d3f26d906204e2ed89efeef597ba810
Remove more unnecessary header includes and use forward declaration.

Change-Id: I88d0fb0e7c20d4b1414516e3bd2f961811b2eb8c