(WIP) Any instance verifying

As mentioned in: https://github.com/allending/Kiwi/issues/295

I was really hoping to have this feature in 3.0 so I started implementing it :)
This PR is not yet ready to merge but I wanted to gather feedback and ideas of what this feature should support. 

As future instances are added to the verifier after init - there are a few (edge) cases with the approach of swizzeling alloc and init will not work, like the example with NSDictionary. What do you guys think about using that approach? Maybe it is worth swizzeling known initializers in foundation?

I would also like to see stubbing support for any instance as it looks to be a good thing in RSpec, thoughts?