Update README.md to fix typo (duplication of word)

Author: sadielbartholomew

README.md

@@ -125,7 +125,7 @@ seprately to the `cf` package.
 
 See the [cf-plot
 gallery](http://ajheaps.github.io/cf-plot/gallery.html) for the full
-range range plotting possibilities with example code.
+range of plotting possibilities with example code.
 
 ![Example output of cf-plot displaying a `cf` field construct](docs/source/images/cfplot_example.png)