Add accessibility labels to hook the views to an automated acceptance test tool

Hey,

I added a few lines of code to add accessibility labels to the views used by default.
That allows to hook them to an automated acceptance test tool (like UIAutomation, Frank, etc.), out of the box. 

That's also very useful for accessibility in general: https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/iPhoneAccessibility/Making_Application_Accessible/Making_Application_Accessible.html

Cheers!
Romain