[inferno-ml] Swap order of elements in makeWrites

[ngua]

We've decided to swap the order of makeWrites so it takes a array of ('a, t) instead of array of (t, 'a) as it currently does. This is to make it consistent with other things that take pairs of values and times.

This is working as far as inferno-ml-server goes (integration tests pass), but we need to do some updates elsewhere before merging this.