Added more error handling and necessary functions

README.md

@@ -14,9 +14,9 @@ go get git.streifling.com/jason/atom@latest
 
 ## Usage
 
-This library provides easy to use functions to safely create and extend elements
-and attributes of an Atom feed. The intended way of using it entails using these
-functions.
+This library provides convenient functions to safely create and extend elements
+and attributes of an Atom feed. This is because it can be hard to know all
+pitfalls of RFC4287. The intended way of using atom is with these functions.
 
 ```go
 package main