Fix build failure

AsyncHttpClient.AsyncHttpResponseFuture was removed from airlift
Fix handling of Hive timestamp in maps/lists

Hive timestamp was serialized as a string when it was in a map/list, but
as a bigint when it was a primitive. This makes it always be serialized
as a bigint of seconds.
Also, add more unit tests for RCFile formats
Add bootstrapped aggregation
Use custom block in bootstrapping to generate poissonized blocks