=act #3725 Make FSMTimingSpec more robust.
=doc #3782 Make IODocSpec say what went wrong
Merge pull request #1885 from akka/wip-3725-make-fsmtimingspec-more-robust-ban

=act #3725 Make FSMTimingSpec more robust.
Merge pull request #1895 from akka/wip-3782-make-iodocspec-say-what-went-wrong-ban

=doc #3782 Make IODocSpec say what went wrong
=pro #3759 Changed to using non-deprecated ScalaTest Matchers
=per #3797 Harden file deletions in persistence tests
Merge pull request #1896 from akka/wip-3759-stop-using-deprecated-scalatest-features-ban

=pro #3759 Changed to using non-deprecated ScalaTest Matchers
Merge pull request #1901 from akka/wip-3797-leveldb-test-cleanup-patriknw

=per #3797 Harden file deletions in persistence tests
Channel and journal plugin API enhancements

- more efficient bookkeeping during delivery and redelivery
- different confirm messages for transient and persistent channels
- journal plugin API now fully batch-oriented
  * added batch-write of confirmations
  * added batch deletions

Todo

- batching of delivery confirmations
- reliable channel enhancements as discussed