Fixes testclient.html; the loading message didn't disappear.
Because of that PMing and challenging others on testclient.html was impossible.
Merge pull request #49 from Quinella/testclientfail

Fixes testclient.html; the loading message didn't disappear.
Added a "persistent notifications" option.
Defaults to yes. If set to no, notifications will disappear automatically after 5 seconds.
The option will only be shown if window.Notification is available.
Renamed "persistent notifications" to "temporary notifications"
Merge pull request #50 from Quinella/notifications

Added a "persistent notifications" option.