Implement $push 2.6 support with $each, $position, $sort, and $slice.
Rewrite compareDBObjects to match mongo 2.6 behavior.
Fix identification of LazyBSONObject as a DBObject.
Change imports style to match project.
Move compareToNullable(...) utility method to Util.
Clarify sort order.
Merge pull request #34 from htmldoug/master-push-2.6

Implement $push 2.6 support with $each, $position, $sort, and $slice.