Downgraded source compatibility to 1.6.
Removed redundant copyright messages.
Extracted EventCallback out of EventBus.
Renamed EventCallback.onNotify(T) to EventCallback.onEvent(T)
Tabs -> spaces.
Added fluid event registration.
Added priority for event delivery.
Altered tests for fluid event registration.
Some generics magic.
Updated README.
Updated README.
Reformating
Merge remote-tracking branch 'remotes/origin/feature/fluid_api'