replace containsString with rangeOfString for iOS 7 support
replace containsString with rangeOfString for iOS 7 support

BranchMetrics/ios-branch-deep-linking,BranchMetrics/ios-branch-deep-linking,BranchMetrics/iOS-Deferred-Deep-Linking-SDK,BranchMetrics/ios-branch-deep-linking,BranchMetrics/ios-branch-deep-linking,BranchMetrics/iOS-Deferred-Deep-Linking-SDK