Issue #1263: Desynchronized nicklist

This is fallout from #1244, which moved models.delNick from using a filter to
using the delete operator.

The delete operator creates a sparse array that has an empty slot for the item
that was deleted. This empty slot is iterable with some constructs, giving a
value of undefined. These unexpected undefined values in the nicklist cause
exceptions to be thrown in some situations, like when calling
models.updateNickSpeak.

To fix this, use Array.splice to remove elements from the nicklist, instead of
the delete operator.

src/js/models.js

@@ -160,7 +160,7 @@ models.service('models', ['$rootScope', '$filter', 'bufferResume', function($roo
             }
             for (i in group.nicks) {
                 if (group.nicks[i].name == nick.name) {
-                    delete group.nicks[i];
+                    group.nicks.splice(i, 1);
                     break;
                 }
             }