Pubsub: One should not stop other bound callbacks on that event from being executed
Merge pull request #92 from mrjoelkemp/fix_one

Pubsub: One should still execute other bound callbacks on an event
trait/pubsub: .one does not modify call array

As caught by #92, .one was modifying the call array during the
iteration. While a forEach iteration over an array guarantees length of
iteration, it will skip the next element if the array is spliced.