Add guava as a dependency to AndroidBuilder.

Change-Id: I4b2029c52099eb449a74f048b5aae6122774e40b
diff --git a/build.gradle b/build.gradle
index cdd921f..5851637 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,5 +1,9 @@
 allprojects {
     apply plugin: 'idea'
 
+    repositories {
+        mavenCentral()
+    }
+
     version = '0.1-SNAPSHOT'
 }