Make abstract_clock members const
Remove deprecated IPAddress
New utility classes, containers, C++14 compatibility, and fixes:
* Add std::equal_to <void> (since C++14)
* Add heterogeneous std::equal (since C++14)
* Add maybe_const
* Add empty_base_optimization
* Add is_constructible specialization for pair, tuple
* Add aged associative containers:
  - aged_set, aged_map, aged_multiset, aged_multimap
  - aged_unordered_set, aged_unordered_map,
  - aged_unordered_multiset, aged_unordered_multimap
* Fix auto keyword pass by reference
* Fix basic_seconds_clock warning and project file