Add support for predicates to IterableSubject

[BlackHC]

It would be nice if there was a way to test predicates on elements of a collection.
assertThat(myList).hasSomeWith(myPredicate); (for an any predicate test), and
assertThat(myList).hasEveryWith(myPredicate); (for an every predicate test).

[kluever]

Will discuss @ API review...thanks for the idea!

[jonas-l]

Categorically testing the contents of collections provides an example on how to achieve hasEveryWith which in your case would be something like assert_().in(myList).thatEach(predicateType).someCheckOnSubject();, however I couldn't find how to do hasSomeWith thus created #188.

[cpovirk]

This is unfair of me for multiple reasons, but I'm going to close this out in favor of #206 to consolidate the discussion.