[Feature Request] Ignore cell magics

[David]

Importing a .ipynb containing cell magic (statements prefixed with %) into a .py file raises an exception; the cell magic isn't recognized. No errors are raised when importing into a .ipynb file.

[Tony Fast]

thanks for this feature request. i'm going to work on implementing this soon.

this feature fits importnb because there is pure python that doesn't require IPython. since magics require IPython we'll add this feature as work around.