PIObject::deleteLater important fix

PIWaitEvent::sleep() method
PITimer thread imp wait optimization, migrate to interruptable sleeps

libs/main/core/piwaitevent_p.cpp

@@ -95,6 +95,27 @@ bool PIWaitEvent::wait(int fd, CheckRole role) {
 }
 
 
+bool PIWaitEvent::sleep(int us) {
+	if (!isCreate()) return false;
+#ifdef WINDOWS
+	DWORD ret = WaitForSingleObjectEx(event, us / 1000, TRUE);
+	ResetEvent(event);
+	return ret == WAIT_TIMEOUT;
+#else
+	int nfds = pipe_fd[ReadEnd] + 1;
+	FD_ZERO(&(fds[CheckRead]));
+	FD_SET(pipe_fd[ReadEnd], &(fds[CheckRead]));
+	timeval timeout;
+	timeout.tv_sec  = us / 1000000;
+	timeout.tv_usec = us % 1000000;
+	int ret = ::select(nfds, &(fds[CheckRead]), nullptr, nullptr, &timeout);
+	int buf = 0;
+	while (::read(pipe_fd[ReadEnd], &buf, sizeof(buf)) > 0);
+	return ret == 0;
+#endif
+}
+
+
 void PIWaitEvent::interrupt() {
 	if (!isCreate()) return;
 #ifdef WINDOWS