text: Title:  iPython notebook keyboard interrupt breaks cell when using Halo
  Body: <!-- Please use the appropriate issue title format:
      BUG REPORT
      Bug: {Short description of bug}
  
      SUGGESTION
      Suggestion: {Short description of suggestion}
  
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      {Question|Discussion|Whatever}: {Short description} -->
  
  
  ## Description
  Currently, in an iPython notebook, if a user does not handle keyboard interrupt and the spinner is running, a `KeyboardInterrupt` is thrown but the spinner keeps spinning.
  
  ### System settings
  
  - Operating System: MacOS
  - Terminal in use: iTerm 2
  - Python version: 2.7.10
  - Halo version: 0.0.8
  
  ### Error
  <!-- Put error here. Exceptions, and full traceback if possible. -->
   
  ### Expected behaviour
  ```
  In [5]: import time
     ...: import random
     ...:
     ...: spinner.start()
     ...: for i in range(100):
     ...:     spinner.text = '{0}% Downloaded dataset.zip'.format(i)
     ...:     time.sleep(random.random())
     ...: spinner.succeed('Downloaded dataset.zip')
     ...:
  ⠹ 4% Downloaded dataset.zip^C---------------------------------------------------------------------------
  KeyboardInterrupt                         Traceback (most recent call last)
  <ipython-input-5-81a625f23371> in <module>()
        5 for i in range(100):
        6     spinner.text = '{0}% Downloaded dataset.zip'.format(i)
  ----> 7     time.sleep(random.random())
        8 spinner.succeed('Downloaded dataset.zip')
        9
  
  KeyboardInterrupt:
  
  ⠼ 4% Downloaded
  ```
  
  ## Steps to recreate
  Following snippet should recreate the error.
  
  ```
  In [1]: from halo import Halo
  
  In [2]: spinner = Halo(text='Downloading dataset.zip', spinner='dots')
  
  In [3]: import time
     ...: import random
     ...:
     ...: spinner.start()
     ...: for i in range(100):
     ...:     spinner.text = '{0}% Downloaded dataset.zip'.format(i)
     ...:     time.sleep(random.random())
     ...: spinner.succeed('Downloaded dataset.zip')
  ```
  
  ## People to notify
  @ManrajGrover
  