Place Kiva docs before Enable docs?

[aaronayres35]

Since Kiva is the lower level library, it might make sense to have the documentation set up so that the kiva docs appear first in the table of contents and then the Enable docs follow (enable builds on kiva so good to understand kiva first?). I could however imagine arguments for leaving it as is.

This is a very minor issue, but trivial to fix if we decide to do so.

[jwiggins]

I feel like the Kiva API is more commonly encountered than the Enable API, so I agree with this suggestion.