Adding support of binding as a struct but resolving as an interface

[dyrkin]

Hi!
First of all, thank your hard work and for this excellent container!

I've added support for instances resolving by an interface, even if they were bound as structs.
We need this as we are trying to make a library that provides different receiver functions. The library knows nothing about containers and uses locally created interfaces about whose the client application knows nothing too. But the client application creates a container with different bound objects that will be used to fill in these resolve functions from the library.
Not sure if my motivation is clear, but I hope so. I can add more details. I would very much appreciate merging this.

[Numichi]

And what is the expected operation if several structs implement the same interface? Which will first? Or find all and give a array?

[dyrkin]

The same can be done for structs. You can bind multiple. But you can name them to resolve the instance you want

[MrVermond]

Could you please extend the documentation to make clear how the change behaves?