- updates lokimq to dev branch
- changes compilation mode to C++17 (which is now required by lokimq,
and already widely applied in lokinet and lokid dev branches)
- replace lokimq::string_view with std::string_view
- replace boost::optional with std::optional, except for:
- boost::optional<std::function<...>> doesn't need optional at all
because a std::function<...> is already nullable.
- boost::optional<T&> isn't supported by std::optional because it
makes little sense (it is just a `T*`) so just switch to T* instead.
* sign cert
* missing changes
* fix bad merge
* use sn_record_t::pub_key() + clang format
* prevent clang format from reordering #includes
* Address reviews
* need travis to find openssl 1.1.1
