adding Square's Otto

RecipientIdeasList was heavily coupled to the RecipientIdeasActivity.
With the Otto Bus in place, the coupling is broken and we're one step
closer to having small, isolated, testable listeners.
let Ideas respond to DeleteIdeaEvent
introducing GotItEvent
introducing Toaster. our highly-coupled listeners can now be extracted
introduce listenerfactory to handle the creation of listeners
move confirmdelete listener to listenerfactory