title: python seaborn lmplot regplot for y-log scale fit
body: <p>I was wondering why seaborn lmplot and regplot only has the option to do logx. I have a frequent use to linearly fit log(y) ~ x and the Y-axis should always be in log scale to show the correlation (as a convention). </p>
  
  <p>Is this something that can be done in Seaborn?</p>
  
  <p>An option of logy=True would be nice...</p>
  
  <p>Thanks.</p>