Update README.md: remove promise of being 'simple' (bad practice)

Author: sadielbartholomew

README.md

@@ -119,13 +119,14 @@ of its array manipulation and can:
 Visualization
 =============
 
-Powerful, flexible, and very simple to produce visualizations of field
-constructs are available with the [cfplot
-package](https://ncas-cms.github.io/cf-plot/build/index.html), that needs to be installed
-seprately to the `cf` package.
+Powerful and flexible visualizations of `cf` field constructs,
+designed to be produced and configured in as few lines of code as
+possible, are available with the [cf-plot
+package](https://ncas-cms.github.io/cf-plot/build/index.html), which
+needs to be installed separately to the `cf` package.
 
 See the [cf-plot
-gallery](https://ncas-cms.github.io/cf-plot/build/gallery.html) for the full
+gallery](https://ncas-cms.github.io/cf-plot/build/gallery.html) for a
 range of plotting possibilities with example code.
 
 ![Example outputs of cf-plot displaying selected aspects of `cf` field constructs](https://raw.githubusercontent.com/NCAS-CMS/cf-plot/master/docs/source/images/cf_gallery_image.png)