Move tool versions into config

Change-Id: Ia75eb20a50571aa6f8ebb80596962694d2d535fa
diff --git a/databinding.properties b/databinding.properties
index 16329ff..72d83b3 100644
--- a/databinding.properties
+++ b/databinding.properties
@@ -5,7 +5,8 @@
 androidPluginVersion = 1.3.0
 javaTargetCompatibility = 1.7
 javaSourceCompatibility = 1.7
-
+buildToolsVersion = 22.0.1
+compileSdkVersionStr = 22
 prebuildFolderName=prebuilds
 group=com.android.databinding
 testGroup=com.android.databinding.test