Install Django==1.7 from PyPi for Tox and Travis

We also drop the "allow_failures" section for Pythons 3.x on Travis.
They should pass consistently now.

I've also adjusted the 'travis' make target to not install Oscar so this
can be called separately as part of the Travis build. Hence, build
errors are reported differently from tests failing.

.travis.yml

 language: python
 
 python:
-  - '2.7'
-  - '3.3'
-  - '3.4'
+    - '2.7'
+    - '3.3'
+    - '3.4'
 
 env:
-  global:
-    # $TRANSIFEX_PASSWORD for oscar_bot (used in transifex.sh)
-    secure: FuIlzEsGJiAwhaIRBmRNsq9eXmuzs25fX6BChknW4lDyVAySWMp0+Zps9Bd0JgfFYUG3Ip+OTmksYIoTUsG25ZJS9cq1IFt3QKUAN70YCI/4ZBLeIdICPEyxq+Km179+NeEXmBUug17RLMLxh3MWfO+RKUHK9yHIPNNpq0dNyoo=
-  matrix:
-    - DJANGO=Django==1.6.6
-    - DJANGO=https://www.djangoproject.com/download/1.7c3/tarball/#egg=Django
+    global:
+        # $TRANSIFEX_PASSWORD for oscar_bot (used in transifex.sh)
+        secure: FuIlzEsGJiAwhaIRBmRNsq9eXmuzs25fX6BChknW4lDyVAySWMp0+Zps9Bd0JgfFYUG3Ip+OTmksYIoTUsG25ZJS9cq1IFt3QKUAN70YCI/4ZBLeIdICPEyxq+Km179+NeEXmBUug17RLMLxh3MWfO+RKUHK9yHIPNNpq0dNyoo=
+    matrix:
+        - DJANGO=Django==1.6.6
+        - DJANGO=Django==1.7
+    install:
+        - make install
+        - easy_install $DJANGO
 
-matrix:
-  allow_failures:
-    - env: "DJANGO=Django==1.6.6"
-      python: '3.3'
-    - env: "DJANGO=Django==1.6.6"
-      python: '3.4'
+    before_script:
+        # Create testing databases for running migrations against
+        - mysql -e 'create database oscar_vagrant;'
+        - psql -c 'create database oscar_vagrant;' -U postgres
+        # Create database for building demo site
+        - psql -c 'create database oscar_demo;' -U postgres
+        - psql -c 'CREATE EXTENSION postgis; CREATE EXTENSION postgis_topology;' -U postgres -d oscar_demo
 
-install:
-  - easy_install $DJANGO
+    script:
+        - make travis
 
-before_script:
-    # Create testing databases for running migrations against
-  - mysql -e 'create database oscar_vagrant;'
-  - psql -c 'create database oscar_vagrant;' -U postgres
-    # Create database for building demo site
-  - psql -c 'create database oscar_demo;' -U postgres
-  - psql -c 'CREATE EXTENSION postgis; CREATE EXTENSION postgis_topology;' -U postgres -d oscar_demo
-
-script:
-  - make travis
-
-after_success:
-  - coveralls
-  # TODO: Re-enable once 0.8 final is released
-  # - ./transifex.sh
+    after_success:
+        - coveralls
+        # TODO: Re-enable once 0.8 final is released
+        # - ./transifex.sh

Makefile

 	pip install -r requirements_vagrant.txt
 	cd sites/sandbox && ./test_migrations.sh
 
-# It is important that this target only depends on install
-# (instead of upgrade) because we install Django in the .travis.yml
-# and upgrade would overwrite it.  We also build the sandbox as part of this target
-# to catch any errors that might come from that build process.
-travis: install lint coverage sandbox demo testmigrations
+# This target is run on Travis.ci. We lint, test and build the sandbox/demo sites as well 
+# as testing migrations apply correctly. We don't call 'install' first as that is run 
+# as a separate part of the Travis build process.
+travis: lint coverage sandbox demo testmigrations
 
 messages:
 	# Create the .po files used for i18n

tox.ini

 [testenv:py27-1.7]
 basepython = python2.7
 deps = -r{toxinidir}/requirements_py2.txt
-       https://www.djangoproject.com/download/1.7c3/tarball/
+       django==1.7
 
 [testenv:py33-1.7]
 basepython = python3.3
 deps = -r{toxinidir}/requirements.txt
-       https://www.djangoproject.com/download/1.7c3/tarball/
+       django==1.7
 
 [testenv:py34-1.7]
 basepython = python3.4
 deps = -r{toxinidir}/requirements.txt
-       https://www.djangoproject.com/download/1.7c3/tarball/
+       django==1.7