Remove CLA mention from CONTRIBUTING.md [ci skip]
Change copy for nation slug prompt alert

Add a hint to the message, which makes it too long
for the alert. To solve, change replace the
now-confusing title ('account' is no longer in the
user-facing vocabulary) with the previous message
in title form.
Add blank launch image for <= iOS 7

Note that ideally the navigation bar is also
included, but this would require manually editing
each version since the bar-height-screen-height
ratio changes.

Instead, we only need to put
http://placehold.it/2048/fff/fff.png into
http://ticons.fokkezb.nl/.
Minor reorganization inside project files
Add launch screen nib for iOS 8