configure: require boost.thread v3

src/lastfm.cpp

@@ -84,7 +84,7 @@ void Lastfm::getResult()
 	w.flush();
 	w.refresh();
 	// reset m_worker so it's no longer valid
-	m_worker = boost::unique_future<LastFm::Service::Result>();
+	m_worker = boost::future<LastFm::Service::Result>();
 }
 
 #endif // HVAE_CURL_CURL_H

src/lastfm.h

@@ -82,7 +82,7 @@ private:
 	std::wstring m_title;
 	
 	std::shared_ptr<LastFm::Service> m_service;
-	boost::unique_future<LastFm::Service::Result> m_worker;
+	boost::future<LastFm::Service::Result> m_worker;
 };
 
 extern Lastfm *myLastfm;