Unlock in threadpool copy ctor

src/threadpool.cpp

@@ -33,6 +33,7 @@ namespace rexy{
 		m_jobs(other.m_jobs),
 		m_valid(true)
 	{
+		m_ctor_lock.unlock();
 		for(size_t i = 0;i < other.m_workers.size();++i){
 			m_workers.emplace_back(&threadpool::worker_loop, this);
 		}