(Collection) factory methods

We have too many methods called of. Because most collections are also functions, I want to simplify that.

• of(T), of(T...)
• ofAll(Iterable)
• ofAll(Iterator) <-- this one might be needed because Iterator (and the upcoming TraversableOnce) will not be Iterable anymore

We need to take a look if ofXyz(Xyz) or fromXyz(Xyz) makes more sense, e.g.

• fromEntries(j.u.Map.Entry...)
• fromEntries(Iterable<? extends j.u.Map.Entry>)
• etc.

Also we will have distinguished factory method names that will not build instances directly from the given method parameters (like of(T...) does for example).

• Stream.iterate(seed, f)
• Tree.recurse(seed, f)
• ...