Introduce a concept of publish to a library.

Test: ./gradlew createArchive no longer includes media-compat-test libraries.
Bug: 64531806
Change-Id: I8e8c1a764443895a5820102994ae96242220f90c
diff --git a/v13/build.gradle b/v13/build.gradle
index 95ff484..d2d7f44 100644
--- a/v13/build.gradle
+++ b/v13/build.gradle
@@ -24,6 +24,7 @@
 
 supportLibrary {
     name 'Android Support Library v13'
+    publish true
     inceptionYear '2011'
     description "The Support Library is a static library that you can add to your Android application in order to use APIs that are either not available for older platform versions or utility APIs that aren't a part of the framework APIs. Compatible on devices running API 14 or later."
 }