Fix validate_on_save class decorator

1.  Change the storategy of the validate_on_save
    It is a class decorator so the default behavior should be ON and
    settings should turn OFF the behavior
2.  Fix the internal storategy
    There were too many problem so I change the internal storategy
    completely
3.  Fix the tests
    The test storategy was not really correct
Implement blog models
Implement EntryFactory
Add validation to Blog Entry model
Add specs for Category
Add specs for Entry
Add permission test cases for Entry
Fix view permission in blogs.entry

Django permission system does not add '_entry' automatically so we have
to specify the permission as 'view_entry' but 'view' in Meta of the
model class.
Merge branch 'feature/blog' of github.com:kawazrepos/third-impact into feature/blog