Switch to side-by-side view

--- a/requirements-common.txt
+++ b/requirements-common.txt
@@ -5,6 +5,7 @@
 Beaker==1.5.4
 BeautifulSoup==3.2.0
 chardet==1.0.1
+colander==0.9.3
 Creoleparser==0.7.3
 datadiff==1.1.3
 decorator==3.3.2