Implement a ``streamize()`` function alias and refactor Stream::streamize()

[nozavroni]

This simply pulls streamize() out of the Stream class and puts it in its own namespaced function so instead of this:

$stream = Stream::streamize("all your base are belong to us");

you do this

$stream = streamize("all your base are belong to us");

Also, add support for accepting anything that implements Iterator by instantiating an IO\IteratorStream object.

• [x] Make streamize() accept SplFileInfo and other Iterators
• [ ] Document it
• [ ] Unit test it

[nozavroni]

Finished... just needs docs and possibly more testing.

[nozavroni]

Closing all issues that only need documentation.