If creating an asset catalog from Xcode, Xcode will
add it to the "Copy Bundle Reources" phase, if it exists.
Since we don't always generate that phase, Xcode will
silently fail with the result that the asset catalog will
not take effect (no icon, launch images etc).
This patch will ensure that we always create the phase
(like native Xcode project does), which will fix the
problem.
Change-Id: Ief949d63543977f1021db992e0c41714d898e68b
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>