Merge pull request #35 from hurshagrawal/fix-multi-fetch-logging

fetch_multi now logs hits/misses correctly
Break out batch association fetching tests into its own file for less hair pulling.
Add support for prefetching non-embedded associations deeply nested under embedded has_many and has_one associations
Fix typo in the test helpers
Merge pull request #32 from Shopify/batched_association_fetches

Deep association batch prefetches
fix to frozen cache keys
add cache_key test