qmake|Unix: Enable C++11

C++11 is now enabled for all g++/clang++ builds.
Cleanup
Refactor|libcore|libcommon: Removed use of auto_ptr

std::auto_ptr is deprecated in C++11. Also, applied established
conventions when returning a MapStateReader via
SavedSession::IMapStateReaderFactory -- just return a pointer to
indicate transfer of ownership.