THBinder tries to update bindings while it is being deallocated

[5sw]

I was using the release 1.0.0 version in an non-ARC project (via cocoapods, THObserversAndBinders is compiled with ARC) and I found a strange crash. After debugging it turned out that the binder was updating its target value while it was being deallocated.

Adding this in THBinder.m fixes the issue for me:

- (void)dealloc
{
    [_observer stopObserving];
}