Removed rtl/ustring.hxx

Change-Id: I626c577e7d8f8a44b5b4f86ebf26d7c321ac84f7
Removed rtl/instance.hxx

Change-Id: Ib0f8eba63ecef918d6f4550ad2e0e9f77ebe1e32
Merge ld:/home/gelma/dev/prg/for_riccardo/slot2 into for_riccardo
Merge ld:/home/gelma/dev/prg/for_riccardo/slot3 into for_riccardo