A couple of fixes I propose

Hi:
- Some fixes to avoid 2 unexpected crashes situations
- Some delegates control better (I think) the behaviour.

I've used your brilliant component for, by using DBCamera, create a Facebook-like camera picker. I've enjoy reading your code, it's very clean.

TODO:
- When startGrid=1, enableGrid=1, enableToolbar=1) and you've seeing the grid for a second time (modally) the toolbar appears unexpectedly.