fixes BOOL adjust which was never NO

[controller
performSelector:@selector(automaticallyAdjustsScrollViewInsets)
withObject:nil] returns id, which cast as BOOL is always YES if not nil.

it can just call the method directly since the the minimum SDK is iOS 7
now. There is no need anymore for respondsToSelector: conditions.
Merge pull request #317 from balord/master

removes some 'respondsToSelector' and 'performSelector' calls since the minimum SDK is iOS7