3.3.0: Query API, Document utilities

• Merged PR #58: Add query API to collections. This adds two new methods
  to the com.mongodb.Collection class, query() and first().
  (@thekid)
• Merged PR #59: Add fields API to Document. This allows addressing fields
  via dot-notation and provides a fluent API to modifications
  (@thekid)
• Merged PR #57: Add Document::create() which creates a document with
  an object ID
  (@thekid)