Change the layout of TP pages and previews

Change the position of the "Keep my wallpaper" checkbox and
make the bottom panel larger, as well as restrict how much
a preview card can grow or shrink depending on the screen
size.

Note that the UX spec cannot be met 100% on all screen
sizes, so for some cases we round to the closest
approximation.

(ConstraintLayout FTW!)

Fixes: 130763357
Fixes: 130398264
Change-Id: I15bece84fb4ce1018676f57d32e0fc533bcdec92
diff --git a/res/layout/theme_option.xml b/res/layout/theme_option.xml
index de81231..1cb9ffa 100644
--- a/res/layout/theme_option.xml
+++ b/res/layout/theme_option.xml
@@ -45,7 +45,8 @@
             android:layout_height="@dimen/theme_option_icon_sample_height"
             android:layout_alignParentTop="true"
             android:layout_alignParentLeft="true"
-            android:layout_margin="@dimen/theme_option_sample_padding"/>
+            android:layout_margin="@dimen/theme_option_sample_padding"
+            android:tint="?android:colorForeground"/>
         <ImageView
             android:id="@+id/theme_option_shape"
             android:layout_width="@dimen/theme_option_shape_sample_width"