Add title blinking on events

When there is an event, blink the title so that a user can know when an
event happens, even if they aren't on that tab. Originally from discussion in and would close #121
I don't believe that clearInterval wipes the variable you pass to it, so blinkInterval will always be defined after the first time it is set. To correct this, I'd change this condition to `if (blinkInterval)` and add `blinkInterval = false` to stopTitleBlink.