Changed minimum permission required for branding bar settings menu 

Jason, similar to the WRAP plugin change we made a while back, the settings panel for the branding bar currently allows anybody with `read` capability to make changes to the URL the search results point to, inject HTML into the branding bar, etc.  I have changed the minimum  capability for making this change to `edit_plugins` similar to the WRAP plugin.  

http://codex.wordpress.org/Roles_and_Capabilities