Fix XCode 5 and iOS 7 warnings

* Remove ARCH settings in xocdeproj for OS X builds
* Remove deprecated and unused trust result from BoxAuthorizationViewController

Fixes GH-63. Fixes GH-54.
Merge pull request #68 from box/xcode-5-ios7-warnings

Fix XCode 5 and iOS 7 warnings
Merge pull request #1 from doo/master

Merge master into doo