this improves load time by 20%.
We switch from shared_ptr to tools::SvRef to manage the objects

I noticed some double inheritance like this:
  DomainMapper
    LoggedProperties
      Properties
        SvRefBase
    LoggedTable
      Table
        SvRefBase
so to be safe I made all the ref-count-base-class inheritance
virtual.

Change-Id: Ia3de9733f5c6966e8171f43d083dcc087040b8cd
Reviewed-on: https://gerrit.libreoffice.org/57022Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>