Update spin.js to v2.3.2 and use it for the agenda scheduling page. Remove the

explicit copy that was kept there. Commit ready for merge.
 - Legacy-Id: 13104

Author: larseggert

ietf/static/ietf/css/agenda/agenda.css

@@ -614,10 +614,7 @@ td#conflict_people_list {
 }
 
 #spinner{
-
-  height:50%;
-  /* margin-top:50%; */
-  /* margin-bottom:50%; */
+  position: relative;
 }