Forward UINavigationController Delegate Methods

[tooolbox]

The Problem

When you enable isHeroEnabled on a UINavigationController, Hero takes over as the delegate for that VC, and saves a reference to its previous delegate in the property previousNavigationDelegate. I've encountered a situation where I want Hero to control the animations of my UINavigationController, but I also want to make another VC aware of these delegate calls.

The Proposal

Whenever Hero receives delegate methods from a UINavigationController, it should call those same methods on the previousNavigationDelegate, if there is one.

I'm working on a PR for this.

[tooolbox]

Interesting, related to #25

[tooolbox]

I was able to solve what I was running into by turning on Hero for the Nav Controller, and then having my own View Controller set itself as the delegate and then forward transition methods to Hero. This way is perfectly workable so I am closing the PR.

[paulpopiel]

FYI fixed in the following:
#430