List dependencies before the things that depend on them

Because we use ordered_pip.sh to install requirements files, we want
dependencies in requirements_dev.txt to be listed _before_ the things
that depend on them, rather than after. Otherwise, with
ordered_pip.sh, stuff will get installed implicitly, and perhaps the
wrong version.

etc/requirements_dev.txt

@@ -22,14 +22,16 @@ mistune==0.5.1
 
 # Example scripts that are run during unit tests use the following:
 
-matplotlib==1.4.3
-# tornado and pyparsing are required by matplotlib
-tornado==4.1
-pyparsing==2.0.3
 # Required by tornado
 backports.ssl-match-hostname==3.4.0.2;python_version<'3.0'
 certifi==14.5.14
 
+# tornado and pyparsing are required by matplotlib
+tornado==4.1
+pyparsing==2.0.3
+
+matplotlib==1.4.3
+
 Markdown==2.6.1
 
 # This --allow syntax is for compatibility with pip >= 1.5