Redirect to unread view after mark notification as read

[osminogin]

In its current form it does not make sense.

You press on the cross (the message is marked as read), but after redirected to the all notification view and still see marked message. It's very simple to fix.

[coveralls]

Coverage remained the same at 89.149% when pulling feeec2c on osminogin:master into dca99e9 on django-notifications:master.

[LegoStormtroopr]

Yeah this seems like a fair call. I like the change.

If there aren't objections in the next day or two I'll organise to pull it in. Thanks!

[osminogin]

Thank you.