title: Numpy: Drop rows with all nan or 0 values
body: <p>I'd like to drop all values from a table if the rows = <code>nan</code> or <code>0</code>.</p>
  
  <p>I know there's a way to do this using pandas i.e <code>pandas.dropna(how = 'all')</code> but I'd like a numpy method to remove rows with all <code>nan</code> or <code>0</code>.</p>
  
  <p>Is there an efficient implementation of this?</p>