Mongo 3.0.0 Compatiblity

change collection.ensureIndex() to collection.createIndex()
Mongo 3.0.0 Compatiblity

change DBRefBase to DBRef
Mongo 3.0.0 Compatiblity

Remove the use of the BSONByteBuffer
Mongo 3.0.0 Compatiblity

Remove the use of a protected deprecated field