Create source and javadoc artifacts.

Issue #12

build.gradle

@@ -63,6 +63,20 @@ subprojects {
 
     task publishSnapshot(dependsOn: ['getCredentials', 'publishMavenJavaPublicationToSnapshotsRepository']) << {
     }
+
+    task javadocJar(type: Jar) {
+        classifier = 'javadoc'
+        from javadoc
+    }
+
+    task sourcesJar(type: Jar) {
+        classifier = 'sources'
+        from sourceSets.main.allSource
+    }
+
+    artifacts {
+        archives javadocJar, sourcesJar
+    }
 }
 
 task wrapper(type: Wrapper) {