Add source jars to maven build

Updated pom.xml so that build will also produce source jars.
Closes issue #32

Author: markphip

pom.xml

@@ -29,6 +29,18 @@
                     <target>1.6</target>
                 </configuration>
             </plugin>
+            <plugin>
+              <groupId>org.apache.maven.plugins</groupId>
+              <artifactId>maven-source-plugin</artifactId>
+              <executions>
+                <execution>
+                  <id>attach-sources</id>
+                  <goals>
+                    <goal>jar</goal>
+                  </goals>
+                </execution>
+              </executions>
+            </plugin>
         </plugins>
     </build>
     <distributionManagement>