PITimeMeasurer remove some API, add elapsedAndReset()

got rid off some warnings

libs/main/io_devices/pisharedmemory.cpp

@@ -136,7 +136,10 @@ bool PISharedMemory::openDevice() {
 		PRIVATE->owner = true;
 		// piCoutObj << "created" << fd;
 	}
-	if (fd >= 0) ftruncate(fd, dsize);
+	if (fd >= 0) {
+		auto _r = ftruncate(fd, dsize);
+		NO_UNUSED(_r);
+	}
 	PRIVATE->data = mmap(0, dsize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 	::close(fd);
 	if (PRIVATE->data == MAP_FAILED) {