Add ServerPingWithAlarmManager to smack-android

smack-android-extensions/build.gradle

@@ -0,0 +1,19 @@
+description = """\
+Extra Smack extensions for Android."""
+
+// Note that the test dependencies (junit, …) are inferred from the
+// sourceSet.test of the core subproject
+dependencies {
+	compile project(':smack-extensions')
+}
+
+compileJava {
+	options.bootClasspath = androidBootClasspath
+}
+
+// See http://stackoverflow.com/a/2823592/194894
+// TODO this doesn't seem to work right now. But on the other hand it
+// is not really required, just to avoid a javadoc compiler warning
+javadoc {
+	options.linksOffline "http://developer.android.com/reference", androidJavadocOffline
+}