- New cluster synchronization logic reuses existing connections.

- Introduced nearest slave server detection.
- Sleep a bit when retrying an individual server during synchronization
  due to socket errors, to avoid punching the system needlessly.

Document inlining of maps, and error out if inlined map keys conflict

with struct fields when encoding.

Merged bson.NewObjectId concurrency fix from tip.

Fixed omitempty on float values, as reported by Otto Bretz.

Introduced ability to provide custom Dial functions.

Server closes cursor when batch is 1. Use 2 instead.

Introduced support for TTL collections.

Fixed tests after bson fixes.

Dropped support for fake runner.

Ensure Apply always goes to the master.