Removes console.warn re keys

[TomClarkson]

No description provided.

[vors]

Got similar warning on the newer version of the app (b0bcbde).
Here is the warning details from XDK:

Warning: Each child in an array or iterator should have a unique "key" prop. Check the render method of `CounterScreen`. See https://fb.me/react-warning-keys for more information.
    in Text (at main.js:203)
    in CounterScreen (at main.js:46)
    in RCTView (at View.js:505)
    in View (at AnimatedImplementation.js:1703)
    in AnimatedComponent (created by DrawerLayout)
    in RCTView (at View.js:505)
    in View (created by DrawerLayout)
    in DrawerLayout (at main.js:41)
    in RCTView (at View.js:505)
    in View (at main.js:40)
    in PomodoroApp (at renderApplication.js:35)
    in RCTView (at View.js:505)
    in View (at AppContainer.js:62)
    in RCTView (at View.js:505)
    in View (at AppContainer.js:61)
    in AppContainer (at renderApplication.js:34)