Expand README.txt for samples to include dependencies

We don't have template integration for README.txt, so we just
recommend the latest build tools and support repository.

Change-Id: I7e0363609caf9de8747ed045d369e6b4f4bf5cb7
diff --git a/templates/base/README.txt b/templates/base/README.txt
index 3f034f4..9616c58 100644
--- a/templates/base/README.txt
+++ b/templates/base/README.txt
@@ -1,6 +1,18 @@
 Build Instructions
 -------------------
+
 This sample uses the Gradle build system. To build this project, use the
 "gradlew build" command or use "Import Project" in Android Studio.
 
-To see a list of all available commands, run "gradlew tasks".
\ No newline at end of file
+To see a list of all available commands, run "gradlew tasks".
+
+Dependencies
+-------------
+
+- Android SDK Build-tools v18.1
+- Android Support Repository v2
+
+Dependencies are available for download via the Android SDK Manager.
+
+Android Studio is available for download at:
+    http://developer.android.com/sdk/installing/studio.html