Add a policy determining how -flatten: should be bounded
Reimplement -switchToLatest with -flatten:withPolicy:
Merge branch 'subscriber-disposal' into backpressure-operators
Clarify that the "wait" policy does not wait on _all_ signals
Merge branch '3.0-development' into backpressure-operators
Reimplement -throttle:valuesPassingTest: with -flatten:
Replace -throttle: with "earliest" and "latest" variants

Resolves #410.
Clarify policies in deprecation messages
Rewrite -flatten: tests for withPolicy: variant
Tests for other flattening policies
CHAGLAG
Remove implementation details from CHANGELOG
Rename "wait" policy to "queue"
Merge pull request #920 from ReactiveCocoa/backpressure-operators

Operator-based backpressure