[boost] [in_place_factory] some suggestions for improvement

Hi, in_place_factory can be quite useful, as I found out recently. However, here are some suggestions to make it event better: 1. add a construction mechanism for arrays 2. add a note to the docs about deduction and using boost::ref 3. have the static 'apply' member function return the pointer to the constructed object - just like the placement new operator 4. use file iteration instead of BOOST_PP_REPEAT for maintainability Regards, Tobias