title: R choroplethrzip package: Modifying scale and legend
body: <p>I am trying to use this package in R to do a map:
  <a href="https://github.com/arilamstein/choroplethrZip" rel="nofollow">https://github.com/arilamstein/choroplethrZip</a></p>
  
  <p>Example code shows like this:</p>
  
  <pre><code>choro = ZipChoropleth$new(zip)
  choro$set_zoom_zip(state_zoom='california', county_zoom=NULL,
                     msa_zoom=NULL, zip_zoom=NULL)
  choro$title = 'My cool title'
  choro$ggplot_scale = scale_fill_brewer(name="", palette=5, drop=FALSE)
  choro$render()
  </code></pre>
  
  <p>Works wonderfully well. But, I am trying to modify the default scale and the legend display using the breaks as follows. But, this does not seem to do anything.</p>
  
  <p>Anyone know how scale_fill_brewer + discrete_scale can be combined together to make a custom fill scale and legend with choroplethrZip? I have data that has the zip column and a value column as the package expects.</p>
  
  <pre><code>choro$ggplot_scale = scale_fill_brewer(breaks = c(1, 100, 1000, 5000,
  10000, 50000, 100000), guide = "legend", name="Georgia Base",         
  palette=5, drop=FALSE)
  </code></pre>