Fix #31 Several backend issues

1) Devicetype was not working like expected in pushnotif view.

2) report view was displayed an error when we try to open .

3) user name was not displayed in Sent To User field in right side of pushnotif view when admin want to sent notification to one or more users.

4) image was not displayed after installed com_ijoomeradv.

5) add a file type field for upload file for live and for Sand box by admin. select option from Deployment Mode in config view.

    - admin can download file if file is already uploaded .

![screenshot-localhost 2014-12-16 12-54-33](https://cloud.githubusercontent.com/assets/9047166/5471914/b39afdae-8620-11e4-92a7-010bdc58fb84.png)




6) extensions icon link was not working.

![screenshot-localhost 2014-12-16 18-17-04](https://cloud.githubusercontent.com/assets/9047166/5471894/8bc3912e-8620-11e4-8939-ccb0e521f109.png)

when we was trying to open above extension it displayed an error.

7) when we was trying to uninstall extension it displayed blank screen so we can't uninstall extension.

8) publish and unpublish button was not working like extected in extension manager of extension view.