Make zipAlignExe come from Build-tools

Also package proguard-project.txt in sdk tools.

Change-Id: I82f61cc60d62c1412bba97e107a59ccecc1d851d
diff --git a/build.gradle b/build.gradle
index d8acb68..350f466 100644
--- a/build.gradle
+++ b/build.gradle
@@ -37,6 +37,10 @@
             into 'ant'
             notice 'files/ant/NOTICE'
         }
+        item('files/proguard-project.txt') {
+            into 'lib'
+            notice null
+        }
 
         item('files/devices.xml') {
             into 'lib'