New menu bar template and fixed reference in delegate

In Yosemite, Hermes doesn't recognize changes in the menu bar from light mode to dark mode resulting in a nearly invisible menu bar icon as shown in the image below. 
![pandora-darkmode](https://cloud.githubusercontent.com/assets/520246/4785596/aa612488-5d81-11e4-9bfa-1e7c00b3b356.png)

This pull request replaces the icon with a .pdf template and changes the reference to the image file in the delegate to allow for the system to display the correct image as shown in the images below.

![new-pandora-darkmode](https://cloud.githubusercontent.com/assets/520246/4785603/da603bb0-5d81-11e4-9ffb-3e0705f01c2a.png)
![new-pandora-lightmode](https://cloud.githubusercontent.com/assets/520246/4785604/da6151da-5d81-11e4-983a-1dbbdc5dbe14.png)

(Note that in the images above, the same file is used in the application resources)