optional_optimization branch

svn path=/sandbox-branches/optional_optimization/boost/optional.hpp; revision=77091
move m_initialized = false ; to destroy()

svn path=/sandbox-branches/optional_optimization/boost/optional/; revision=77153
has_trivial_destructor and dtor optimization done.

svn path=/sandbox-branches/optional_optimization/boost/optional/; revision=77235
has_trivial_copy and basic copy optimization done

svn path=/sandbox-branches/optional_optimization/boost/optional/; revision=77237
used dtor_optimized in destroy for branch free destroy

svn path=/sandbox-branches/optional_optimization/boost/optional/; revision=77238