make video cache feature optional

ios/Video/UIView+FindUIViewController.m

@@ -0,0 +1,21 @@
+//  Source: http://stackoverflow.com/a/3732812/1123156
+
+#import "UIView+FindUIViewController.h"
+
+@implementation UIView (FindUIViewController)
+- (UIViewController *) firstAvailableUIViewController {
+    // convenience function for casting and to "mask" the recursive function
+    return (UIViewController *)[self traverseResponderChainForUIViewController];
+}
+
+- (id) traverseResponderChainForUIViewController {
+    id nextResponder = [self nextResponder];
+    if ([nextResponder isKindOfClass:[UIViewController class]]) {
+        return nextResponder;
+    } else if ([nextResponder isKindOfClass:[UIView class]]) {
+        return [nextResponder traverseResponderChainForUIViewController];
+    } else {
+        return nil;
+    }
+}
+@end