DATAREST-228 - Added Maven Enforcer plugin to ensure project is built with Java 7.

Original pull request: #131.

pom.xml

@@ -59,7 +59,7 @@
 			<roles>
 				<role>Developer</role>
 			</roles>
-			<timezone>-5</timezone>
+			<timezone>-6</timezone>
 		</developer>
 	</developers>
 
@@ -125,6 +125,29 @@
 
 	</dependencies>
 
+	<build>
+		<plugins>
+			<plugin>
+				<artifactId>maven-enforcer-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>enforce-rules</id>
+						<goals>
+							<goal>enforce</goal>
+						</goals>
+						<configuration>
+							<rules>
+								<requireJavaVersion>
+									<version>[1.7,1.8)</version>
+								</requireJavaVersion>
+							</rules>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
 	<repositories>
 		<repository>
 			<id>spring-libs-snapshot</id>