:lipstick: Remove code duplication around emitting events

There was code in a number of places that formatted the event names differently depending on whether the event was for a theme or a package. This change creates an `emitPackageEvent` method that standardizes the logic for determining if the event is for a package or a theme and emits the properly formatted event.

Caveat: It makes searching for the source of a given event more difficult.

I was looking at the code for something else I wanted to work on, saw this pattern and figured I could clean it up a little first. Totally cool if this isn't the direction you want to go, it's just something I whipped up :smile:
I re-toggled the travis hook so hopefully your next push should actually build with specs running.

I'm not sure you need to test this directly, it is probably covered already by existing specs that are relying on these events for UI updates and such.