Added maven source plugin

* This allows the viewing of the sources from within an IDE when building against Slimefun.

pom.xml

@@ -40,6 +40,20 @@
             </testResource>
         </testResources>
         <finalName>${project.name} v${project.version}</finalName>
+        <plugins>
+            <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>
         <resources>
             <resource>
                 <directory>${basedir}/src</directory>