Bugfix admin selects talk

Was getting some JS errors when attempting to select a talk. Turned out to be a simple misspelling in the TalksController.  I corrected that and also removed a CSS reference to an image that no longer exists. 

[Same story](https://github.com/chartjes/opencfp/pull/136) on tests with this PR, I'm going to go through and start working on coverage of primary features to help identify this type of thing happening.

Image of bug:

![image](https://cloud.githubusercontent.com/assets/2453394/4342203/27eac290-4042-11e4-9c00-3d36149f4563.png)

Fixed:

![image](https://cloud.githubusercontent.com/assets/2453394/4342211/345cdd88-4042-11e4-9d93-286a54e783bb.png)