Fixing invitation tests
Updating changelog
Merge pull request #144 from taigaio/notification-refactor

Notification refactor
Fixing error when importing issues, the finished date was set to none by signals. Added some tests
Merge pull request #142 from taigaio/bug/1438/error-when-import-export-finish-date-for-issues-and-user-stories

Fixing error when importing issues, the finished date was set to none by signals. Added some tests
Total milestones must never be null
Merge pull request #146 from taigaio/bug/1466/projects-with-null-total-milestones

Total milestones must never be null
Fixing problem with new notifications system on upload 2 equal attachments.