Smarter overloading with iterables

[Mego]

• If at first we don't succeed, try vectorizing
• Other stuff?

[evlrobinson]

To that end, I'll start a list of commands that don't work with iterables.

1. ╨ (permutations) doesn't work with H (head), t (tail), í (index)
2. Z (zip) doesn't work with S (sort)

[Mego]

Monads

[Mego]

The linked commit fixes the specific issues mentioned in @sherlock9's comment. As further issues come up, they will be fixed similarly. The issue is caused by commands that need to evaluate an entire iterable to work not properly handling generators. This will be fully fixed by a large-scale rewrite that is in progress, that uses monadic types internally to handling the various overloads of commands and apply them correctly to the various possible types that might be present.