prefetch() now loads all foreign keys to given table
Yay, all checks have passed.
 I've pushed a branch that has some of your changes integrated, 89cd2c4f74a526591f3804d04b2252c489be5432
 That's great, thanks!
 Pushed 2f028c32225c5aad9b97f0f451b9d238c3846e0d to the `multiprefetch` branch. Things aren't working quite right in the test-case. I think the identity map needs to differentiate things by field, but haven't dug into it too much yet.
 Got things fixed and have merged into master.
