Eleven: Switch default artist and album to a more colorful version

Also fixed a bug where playlist worker tasks were running more than necessary
Removed the picker to fetch images from internet
because last.fm is removed for now

Change-Id: Ice438ac650d8b7be0c275f8270af13086e6568d6

res/layout-v16/notification_template_expanded_base.xml

@@ -28,7 +28,6 @@
         android:layout_height="@dimen/notification_expanded_height"
         android:layout_alignParentBottom="true"
         android:layout_alignParentLeft="true"
-        android:background="@drawable/default_artwork"
         android:scaleType="fitXY" />
 
     <LinearLayout

res/layout/app_widget_large.xml

@@ -29,7 +29,6 @@
         android:layout_height="@dimen/notification_expanded_height"
         android:layout_rowSpan="3"
         android:layout_marginBottom="@dimen/app_widget_bottom_margin"
-        android:background="@drawable/default_artwork_sm"
         android:scaleType="fitXY" />
 
     <LinearLayout

res/layout/app_widget_large_alternate.xml

@@ -27,7 +27,6 @@
         android:id="@+id/app_widget_large_alternate_image"
         android:layout_width="@dimen/app_widget_large_alternate_artwork_size"
         android:layout_height="@dimen/app_widget_large_alternate_artwork_size"
-        android:background="@drawable/default_artwork_sm"
         android:scaleType="fitXY" />
 
     <LinearLayout

res/layout/app_widget_small.xml

@@ -29,7 +29,6 @@
         android:id="@+id/app_widget_small_image"
         android:layout_width="@dimen/app_widget_small_artwork_size"
         android:layout_height="@dimen/app_widget_small_artwork_size"
-        android:background="@drawable/default_artwork_sm"
         android:contentDescription="@null"
         android:scaleType="centerInside" />