=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
=per #3797 Additional hardening of persistence tests

* Pass system properties to forked tests
* revert Cleanup.afterTermination
* increase timeout for first assert in failing tests
Merge pull request #1906 from akka/wip-3797-persistence-tests-patriknw

=per #3797 Additional hardening of persistence tests
=act #3800: Add timeout value in AskTimeoutException message.