Remove dismissive language from intro to GitHub Pages

Closes #174.

Author: alex-ball

episodes/05-github-pages.md

@@ -21,10 +21,10 @@ exercises: 20
 
 ## GitHub Pages
 
-GitHub Pages is a simple service to publish a website directly on GitHub from a Git repository.
+GitHub Pages is a service for publishing a website directly on GitHub from a Git repository.
 You add some files and folders to a repository and GitHub Pages turns it into a website.
 You can use HTML directly if you like, but they also provide Jekyll,
-which renders Markdown into HTML and makes it really easy to setup a blog or a template-based website.
+a tool that can build a blog or a template-based website from a set of Markdown files.
 
 ### Why GitHub Pages is awesome!