Linked lists

[danilopedraza]

Some features encourage to use some cons based programming patterns. The motivation for these patterns is that linked lists are under the hood. However, Komodo does not have linked lists. They should be added.

I propose this syntax:

let isLL(%[..]) := true
let isLL(_) := false

assert(%[].isLL())

They clearly should allow the cons syntax (%[first|tail]). I don't know if they should allow access by index. Probably not.