Added issue about repeating images that are used as exclusions

Author: vhardy

css3-exclusions/Exclusions.src.html

@@ -839,6 +839,9 @@ <h3 id="shapes-from-image">Shapes from Image</h3>
           them. In order to avoid that, another exclusion element can be overlaid.
       </p>
 
+      <div class="issue issue-marker"><p class="desc">Do we need to provide properties to repeat exclusion
+          images as for the background-image property?</p></div>
+      
       <!-- End section "Shapes from image" -->
 
       <h3 id="declaring-shapes">Declaring Shapes</h3>