title: Installing "loo" package in R - source vs binary?
body: <p>I am trying to install the "loo" package in R as it is a dependency for another library I am trying to run ("rethinking"). It keeps failing. At first I got an error saying that loo only runs on R >= 3.1.2 (I was running 3.0.1) so I did an update to 3.1.2. Now I try and install the package it it says</p>
  
  <p>package ‘loo’ is available as a source package but not as a binary</p>
  
  <p>Warning message:
  package ‘loo’ is not available (for R version 3.1.2) </p>
  
  <p>I don't understand how it is not available for R version 3.1.2 after one night? Is there a way to install a source package differently? I am working on a mac, if that helps.</p>