DATAMONGO-1444 - Add support for RxJava wrapper types and slice queries.

Reactive MongoDB repository can now be composed from Project Reactor and RxJava types for method arguments and return types. Query methods and methods from the base/implementation classes can be invoked with a conversion of input/output types.

spring-data-mongodb-cross-store/pom.xml

@@ -51,6 +51,14 @@
 			<version>2.0.0.BUILD-SNAPSHOT</version>
 		</dependency>
 
+		<!-- reactive -->
+		<dependency>
+		 	<groupId>io.projectreactor</groupId>
+			<artifactId>reactor-core</artifactId>
+			<version>${reactor}</version>
+			<optional>true</optional>
+		</dependency>
+
 		<dependency>
 			<groupId>org.aspectj</groupId>
 			<artifactId>aspectjrt</artifactId>