DATAMONGO-1176 - Polishing.

- Remove dropDups assertion as the MongoDB 3 driver does no longer provide dropDups even if running agains a MongoDB v2.6.7.
- Remove mongo-next build profile as we're based on the Mongo 3 driver now.
- Map update object and merge set operations.

pom.xml

@@ -113,22 +113,6 @@
 	</developers>
 
 	<profiles>
-		<profile>
-
-			<id>mongo-next</id>
-			<properties>
-				<mongo>2.15.0-SNAPSHOT</mongo>
-			</properties>
-
-			<repositories>
-				<repository>
-					<id>mongo-snapshots</id>
-					<url>https://oss.sonatype.org/content/repositories/snapshots</url>
-				</repository>
-			</repositories>
-
-		</profile>
-
 		<profile>
 
 			<id>mongo3</id>