Add checkpoint and restore to client package

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

reaper/reaper.go

@@ -70,13 +70,13 @@ func (m *Monitor) Start(c *exec.Cmd) error {
 		c:      c,
 		ExitCh: make(chan int, 1),
 	}
-	m.Lock()
-	defer m.Unlock()
 	// start the process
 	if err := rc.c.Start(); err != nil {
 		return err
 	}
+	m.Lock()
 	m.cmds[rc.c.Process.Pid] = rc
+	m.Unlock()
 	return nil
 }