enable automated testing on python 3.5

Drops support for python 3.3, since django no longer supports
it. See the failure here:
  https://travis-ci.org/tzangms/django-bootstrap-form/jobs/94785903

If python 3.3 support is still needed, we can configure it to
run only on versions of django < 1.9.

.travis.yml

@@ -2,8 +2,8 @@ language: python
 
 python:
   - "2.7"
-  - "3.3"
   - "3.4"
+  - "3.5"
 
 install:
   - pip install coverage coveralls

bootstrapform/tests.py

@@ -38,7 +38,7 @@ class BootstrapTemplateTagTests(TestCase):
     maxDiff = None
 
     def setUp(self):
-        call_command('syncdb', interactive=False)
+        call_command('migrate', interactive=False)
 
     def test_basic_form(self):
         form = ExampleForm()

setup.py

@@ -13,8 +13,8 @@ setup(
         "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.3",
         "Programming Language :: Python :: 3.4",
+        "Programming Language :: Python :: 3.5",
     ],
     keywords='bootstrap,django',
     author='tzangms',