Use the UIToolBar of the UINavigationController instead of creating your own.

**Is your feature request related to a problem? Please describe.**
Currently, if you create the UIViewcontroller by programming, you have to create and position your own UIToolbar.

**Describe the solution you'd like**
I would love it if it worked directly with "self.navigationcontroller.toolbar". Just add it to the "followers" and you're done.

**Describe alternatives you've considered**
At present, extensive programming work is necessary to achieve the desired result.

**Additional context**
It would make it much easier to work with this framework, as the ScrollingNavigationController class already exists.