Fix the "delete site" overlay. 

#6100 

This PR addresses comments in #6100. The "vsite/delete" is now an overlay without the hwpi theme.
Before:
![selection_392](https://cloud.githubusercontent.com/assets/4497748/3653891/33d30698-115e-11e4-826c-247e21452cb4.png)

After:
![selection_394](https://cloud.githubusercontent.com/assets/4497748/3653898/5eed4546-115e-11e4-87ec-dda5f32e7a07.png)

As for the email, it is sent to the site email variable by default.
If I change it to ``ran@gizra.com`` I get a confirmation message and an email for delete request:
![selection_388](https://cloud.githubusercontent.com/assets/4497748/3653907/79ab1480-115e-11e4-9161-c7382d19d0cf.png)
![selection_389](https://cloud.githubusercontent.com/assets/4497748/3653906/79a93a0c-115e-11e4-834d-287e0cfb8591.png)