Fix python test -- Related to #2490
Initial fixes to make ruby driver work with threads.
Ruby style fix.
Ruby driver bug and concurrency fixes.
Replaced boost_function_callback_t with std_function_callback_t.
Replaced boost/function.hpp include in coro_pool.hpp.
Removed boost/bind.hpp include from watchable.tcc.
Removed boost/bind.hpp from directory_echo.tcc.
Removed boost/bind.hpp from cross_thread_watchable.tcc.
Removed boost/bind from other header files.
Made watchable_t and the like use std::function.
Removed boost/function.hpp from watchable.hpp.
Made json_adapter.hpp not include boost/function.hpp.
Removed boost/function.hpp from semilattice/view.hpp.
Removed boost/function.hpp from death_runner.hpp.
Removed boost/function from network.hpp.
Removed bosot/functionh.pp from clustering_utils.hpp.
Removed boost/function.hpp from arch/io/disk headers.
Removed boost/function.hpp from multistore.hpp.
Removed some last boost/function includes.