Convert much of the regression tests to use absolute imports. There's still work to be done though.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16976 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/cache/models.py

@@ -1,6 +1,8 @@
-from django.db import models
 from datetime import datetime
 
+from django.db import models
+
+
 def expensive_calculation():
     expensive_calculation.num_runs += 1
     return datetime.now()