Strange behavior with multiple modal views.

[bfeher]

If you open an MHDismissModalView controller, scroll, then segue to another MHDismissModalView controller from the first one, upon closing the second, it goes back to the view controller which launched the first instead of going back to the first MHDismissModalView controller. After the segue completes, the first MHDismissModalView controller then instantly appears. This is unexpected and causes a weird visual interrupt to app flow.

To explain better, take View Controller A, and 2 MHDismissModalView controllers B* and C*:

1. A --[modal segue]--> B*
2. scroll on B* (this is required to replicate the issue)
3. B* --[modal segue]--> C*
4. Pull down to close C* causes us to see A underneath, instead of B_, until the segue finishes, at which time B_ appears out of nowhere. (We should only see B* underneath C*, not A.)

[bfeher]

This bug is reproducible using the demo project.

1. Run demo MHDismissModalView.xcodeproj
2. Tap the button on top titled "view"
3. Pull down a bit, but don't close it.
4. Tap the button titled "present"
5. pull to dismiss.