grade: dependency cleanup/updates

* remove unused dependencies:
    - robotium
    - libphonenumber
    - stickylistheaders

* update dependencies:
No major update, these are point-releases only
    - zxing-android to 3.5, core to 3.3
    - butterknife to 8.6.0
    - dagger to 2.11
    - glide 3.8.0

Change-Id: I2b41c6d00ab37d5ee08afbe2cb457c1253c00412
Reviewed-by: Hadrien De Sousa <hadrien.desousa@savoirfairelinux.com>
diff --git a/ring-android/libringclient/build.gradle b/ring-android/libringclient/build.gradle
index aa28920..1e5def1 100644
--- a/ring-android/libringclient/build.gradle
+++ b/ring-android/libringclient/build.gradle
@@ -12,7 +12,7 @@
     }
 
     // QRCode encoding
-    compile 'com.google.zxing:core:3.2.1'
+    compile 'com.google.zxing:core:3.3.0'
 
     // dependency injection
     compile 'javax.inject:javax.inject:1'