[boost] [property_tree iostreams smart_ptr] Warning fixes

Dear all, I have submitted pull requests for mostly warning fixes. 3 of them are still open. https://github.com/boostorg/property_tree/pull/15/files https://github.com/boostorg/iostreams/pull/19 https://github.com/boostorg/smart_ptr/pull/18 Could someone merge them in, so we have this fixed for 1.60. That would be nice. Thanx in advance Joachim -- Interval Container Library [Boost.Icl] http://www.joachim-faulhaber.de