Use material overflow icon in decrypt list

Conflicts:
	OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/BaseNfcActivity.java
	OpenKeychain/src/main/res/layout/decrypt_list_entry.xml

Graphics/get-material-icons.sh

@@ -47,6 +47,7 @@ python copy OpenKeychain communication grey email 24
 python copy OpenKeychain social black share 24
 python copy OpenKeychain content black content_copy 24
 python copy OpenKeychain communication black chat 24
+python copy OpenKeychain navigation black more_vert 24
 
 # navigation drawer sections
 python copy OpenKeychain communication black vpn_key 24

OpenKeychain/src/main/res/layout/decrypt_list_entry.xml

@@ -90,11 +90,12 @@
 
                 <ImageView
                     android:id="@+id/context_menu"
-                    android:layout_width="wrap_content"
+                    android:scaleType="center"
+                    android:layout_width="36dip"
                     android:layout_height="48dip"
                     android:clickable="true"
-                    android:background="?android:selectableItemBackground"
-                    android:src="@drawable/ic_menu_moreoverflow_normal_holo_light" />
+                    android:background="?attr/selectableItemBackgroundBorderless"
+                    android:src="@drawable/ic_more_vert_black_24dp" />
 
             </LinearLayout>