Implemented window coord mirroring for RTL. This

  Implemented window coord mirroring for RTL. This
    is only implemented for *setting* the coordinates
    which is enough for wxSizers and 99% or other
    dialogs to work.
  Also reversed the meaning of wxStaticText alignment
    in RTL mode. It is possible that later versions
    of GTK actually do that themselves. (?)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@41137 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775