add format change ui, send a hips_removed event when a layer changes

examples/al-cat-proper-motion.html

@@ -62,7 +62,7 @@
             s.dec,
             s.ra + dra,
             s.dec + ddec,
-            {lineWidth: 3, color}
+            {color}
           )
         }
       });

examples/al-init-custom-options.html

@@ -25,6 +25,7 @@
                 showZoomControl:true,
                 showSettingsControl:true,
                 showCooGrid: true,
+                fullScreen: true,
             }
         );