Cell model closures should receive dataSource/delegate function params

[jessesquires]

Most of the closures for cells at () -> Void
https://github.com/plangrid/ReactiveLists/blob/master/Sources/Typealiases.swift#L19-L32

Instead, the should receive the params from the method in which they are called, for example:
typealias DidSelectClosure = (tableView, indexPath) -> Void

It's not uncommon to need access to these values to perform certain operations.

---

Also of note:

Why not just define functions on the *CellViewModel` protocols? Seems like a much simpler design. No need for the typealiases.