text: Title: Provide option to render more than one spinner at the same time
  Body: Suppose you get multiple long tasks at hand. 
  It should be nice to be able to start more than one spinner before finishing the last one
  
  take this as an example:
  
   
  ```
   from halo import Hal
   
   a = start_task_a()
   a_spinner = Halo({'text': 'Do A', 'spinner': 'dots'})
   a_spinner.start()
   a_is_spinning = True
   
   b = start_task_b()
   b_spinner = Halo({'text': 'Do B', 'spinner': 'dots'})
   b_spinner.start()
   b_is_spinning = True
   
   while a_is_spinning or b_is_spinning:
       if a.is_finished():
           a_spinner.succeed()
           a_is_spinning = False
       if b.is_finished():
           b_spinner.succeed()
           b_is_spinning = False
  ```
   