Expose itertools on observable/iterator

[dy]

https://github.com/tc39/proposal-iterator-helpers

That would remove the need in creating v every here and there:

// now: every here and there, but transform should be used for _calc_!
v(ticker, v => 'Count: ' + v)

// proposed:
ticker.map(v => 'Count: ' + v)

Makes code clean and v instance more meaningful as class #207.

It may follow rxjs operators / array methods as minimal subset:

• .map(fn)
• .filter(fn)
• .reduce((acc, curr) => acc, init)

filter/reduce btw is not simply possible with v.

That will alleviate the v/f fuse - v can be used more as value container, not as transform.

[dy]

That will be covered when itertools are getting a bit closer to standard.