added Sequence#chunk
added Sequence#tap
updated changelist w/ AsyncSequence methods that now return promises
implemented promise-based AsyncSequence#toArray
updated comments on AsyncSequence

this promise stuff is happening now
added better documentation for ObjectWrapper#watch
implemented AsyncSequence#indexOf the promise-y way
added promise support for AsyncSequence#contains
added promise interface to AsyncSequence#toObject
implemented promise interface for AsyncSequence#toString
bumping to 0.3.0 because of all this promise stuff