add a short text to tactile paving quest (fixes #762)

app/src/main/res/layout/quest_tactile_paving.xml

@@ -1,16 +1,22 @@
 <?xml version="1.0" encoding="utf-8"?>
-<RelativeLayout
+<LinearLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
-    android:gravity="bottom">
+    android:orientation="vertical">
+
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:text="@string/quest_generic_looks_like_this"/>
 
     <ImageView
         android:id="@+id/tactilePavingImage"
-        android:layout_width="wrap_content"
+        android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:adjustViewBounds="true"
         android:cropToPadding="false"
+        android:scaleType="centerCrop"
         android:src="@drawable/tactile_paving_illustration" />
 
-</RelativeLayout>
+</LinearLayout>

app/src/main/res/values/strings.xml

@@ -450,4 +450,5 @@ Otherwise, you can download another keyboard in the app store. Popular keyboards
     <string name="invalidation_dialog_message">Invalidating the cache causes the quests to be updated next time they are downloaded each. The quest cache is invalidated automatically after one week and immediately when a quest you solved turns out to be already answered by someone else.</string>
     <string name="quest_openingHours_emptyAnswer">You need to describe what is on the sign. If there is no sign, you should ask for the opening hours inside.</string>
     <string name="quest_cycleway_value_none_but_no_oneway">none, but cyclists may use road in both directions</string>
+    <string name="quest_generic_looks_like_this">Usually looks like this:</string>
 </resources>