Publish apksig library on jcenter

This modifies the Gradle build script used by Android Plugin for
Gradle to publish apksig on jcenter with the same cadence as the
Android Plugin for Gradle is published there.

Test: ./gradlew :apksig:bintrayUpload
https://code.google.com/p/android/issues/detail?id=227935
Bug: 33158935

Change-Id: I7b38713eceaaad7b7d9cc30a58ab934e97a154bf
diff --git a/android_plugin_for_gradle.gradle b/android_plugin_for_gradle.gradle
index 14a4d35..0041570 100644
--- a/android_plugin_for_gradle.gradle
+++ b/android_plugin_for_gradle.gradle
@@ -2,8 +2,13 @@
 
 apply from: "$rootDir/buildSrc/base/baseJava.gradle"
 
-apply plugin: 'maven'
-
 group = "com.android.tools.build"
 archivesBaseName = 'apksig'
 version = rootProject.ext.buildVersion
+
+project.ext.pomName = 'Android Tools apksig library'
+project.ext.pomDesc = 'Library for signing APKs and for checking that APK signatures verify on Android'
+
+apply from: "$rootDir/buildSrc/base/publish.gradle"
+apply from: "$rootDir/buildSrc/base/bintray.gradle"
+apply from: "$rootDir/buildSrc/base/javadoc.gradle"