allow to exclude discarded contracts from selection

index.html

@@ -30,6 +30,11 @@
     <input id="hops" type="checkbox" checked="checked"/><label for="hops">Hops</label>
 </div>
 
+<div id="other" class="filters">
+    <span>Other:</span>
+    <input id="discarded" type="checkbox" checked="checked"/><label for="discarded">Discarded</label>
+</div>
+
 <div id="included">
 </div>
 <hr style="clear: left;height:5px;border-width:0;color:gray;background-color:darkgoldenrod"/>