Update Support library gradle build files WIP

Means we can now develop the support lib using
Android Studio and Gradle.

Need to update the Gradle prebuilts.

Change-Id: I788c6105185b5681267d6ad9a8a8b875fc4e57a6
diff --git a/v7/recyclerview/build.gradle b/v7/recyclerview/build.gradle
index 4d0b564..550e39e 100644
--- a/v7/recyclerview/build.gradle
+++ b/v7/recyclerview/build.gradle
@@ -9,7 +9,6 @@
 
 android {
     compileSdkVersion 7
-    buildToolsVersion "19.0.1"
 
     defaultConfig {
         minSdkVersion 7
@@ -31,7 +30,7 @@
 android.libraryVariants.all { variant ->
     def name = variant.buildType.name
 
-    if (name.equals(com.android.builder.BuilderConstants.DEBUG)) {
+    if (name.equals(com.android.builder.core.BuilderConstants.DEBUG)) {
         return; // Skip debug builds.
     }
     def suffix = name.capitalize()
@@ -42,9 +41,9 @@
         from 'LICENSE.txt'
     }
     def javadocTask = project.tasks.create(name: "javadoc${suffix}", type: Javadoc) {
-        source android.sourceSets.main.allJava
+        source android.sourceSets.main.java
         classpath = files(variant.javaCompile.classpath.files) + files(
-                "${android.plugin.sdkDirectory}/platforms/${android.compileSdkVersion}/android.jar")
+                "${android.sdkDirectory}/platforms/${android.compileSdkVersion}/android.jar")
     }
 
     def javadocJarTask = project.tasks.create(name: "javadocJar${suffix}", type: Jar) {
@@ -54,7 +53,7 @@
 
     def sourcesJarTask = project.tasks.create(name: "sourceJar${suffix}", type: Jar) {
         classifier = 'sources'
-        from android.sourceSets.main.allSource
+        from android.sourceSets.main.java.srcDirs
     }
 
     artifacts.add('archives', javadocJarTask);