Updated the django-filter version and added tests against Django 1.7a1

.travis.yml

@@ -7,6 +7,7 @@ python:
   - "3.3"
 
 env:
+  - DJANGO="https://www.djangoproject.com/download/1.7a1/tarball/"
   - DJANGO="django==1.6"
   - DJANGO="django==1.5.5"
   - DJANGO="django==1.4.10"
@@ -20,7 +21,7 @@ install:
   - "if [[ ${TRAVIS_PYTHON_VERSION::1} != '3' ]]; then pip install django-oauth2-provider==0.2.4; fi"
   - "if [[ ${TRAVIS_PYTHON_VERSION::1} != '3' ]]; then pip install django-guardian==1.1.1; fi"
   - "if [[ ${DJANGO::11} == 'django==1.3' ]]; then pip install django-filter==0.5.4; fi"
-  - "if [[ ${DJANGO::11} != 'django==1.3' ]]; then pip install django-filter==0.6; fi"
+  - "if [[ ${DJANGO::11} != 'django==1.3' ]]; then pip install django-filter==0.7; fi"
   - export PYTHONPATH=.
 
 script:
@@ -28,6 +29,8 @@ script:
 
 matrix:
   exclude:
+    - python: "2.6"
+      env: DJANGO="https://www.djangoproject.com/download/1.7a1/tarball/"
     - python: "3.2"
       env: DJANGO="django==1.4.10"
     - python: "3.2"