Merge pull request #83 from google/add_sources.jar_to_artifact

Add sources.jar as part of the build artifacts.

flexbox/maven.gradle

@@ -50,3 +50,12 @@ install {
         }
     }
 }
+
+task sourcesJar(type: Jar) {
+    from android.sourceSets.main.java.srcDirs
+    classifier = 'sources'
+}
+
+artifacts {
+    archives sourcesJar
+}