Ensure testing deps don't clobber package ones

Installing the requirements.txt after running 'setup.py develop' can
cause problems as it doesn't respect the version ranges from setup.py.
This was picked up by Hudson which was installing Django==1.5 when
upgrading django-nose.

This is addresses by:

* Adding Django to requirements.txt
* Running 'setup.py develop' AFTER installing requirements.txt

Makefile

@@ -2,12 +2,12 @@
 .PHONY: contribute ci test i18n lint travis
 
 install:
-	python setup.py develop
 	pip install -r requirements.txt --use-mirrors
+	python setup.py develop
 
 upgrade:
-	python setup.py develop --upgrade
 	pip install --upgrade -r requirements.txt --use-mirrors
+	python setup.py develop --upgrade
 
 sandbox: install
 	-rm -f sites/sandbox/db.sqlite

requirements.txt

@@ -13,6 +13,10 @@ Sphinx>=1.1.3,<1.2
 django-dynamic-fixture>=1.6.4,<1.7
 mock>=1.0.1,<1.1
 coverage>=3.6,<3.7
+# We specify Django here as CI installs these requirements with the --upgrade
+# option which will ignore the Django requirements from setup.py and possibly
+# bump it to an unsupported version.  Django-nose install Django.
+django<1.5
 django-nose>=1.1,<1.2
 nose<1.2
 # Use a slightly older version of nose-progressive to play nicely