Samples Build: Update build-tools to v19

Use SDK Build-tools v19 as dependency for all samples.

Change-Id: I83a2180406e7d26b0f61d93dadd6c0f0bdab033f
diff --git a/templates/base/_MODULE_/build.gradle.ftl b/templates/base/_MODULE_/build.gradle.ftl
index fd740a3..86365e3 100644
--- a/templates/base/_MODULE_/build.gradle.ftl
+++ b/templates/base/_MODULE_/build.gradle.ftl
@@ -52,7 +52,7 @@
      <#-- Note that target SDK is hardcoded in this template. We expect all samples
           to always use the most current SDK as their target. -->
     compileSdkVersion ${compile_sdk}
-    buildToolsVersion "18.0.1"
+    buildToolsVersion "19"
 
     sourceSets {
         main {