Prepare v0.7.1 release

Author: clue

CHANGELOG.md

@@ -4,7 +4,7 @@ This file is a manually maintained list of changes for each release. Feel free
 to add your changes here when sending pull requests. Also send corrections if
 you spot any mistakes.
 
-## 0.7.1 (2014-xx-xx)
+## 0.7.1 (2014-03-12)
 
 *   Fix: Throwing an `UnexpectedValueException` if writing GraphViz Dot script
     to a temporary file fails and remove its debugging output