Scalatest: BeforeAndAfterAll can be stacked

When using scalatest and spray-testkit, there may be multiple traits implementing BeforeAndAfterAll in a test.
To ensure that all of them are called, ScalatestInterface should call the super implementation. 
Remove outdated comment about by call-by-name route.
echo-server example: extend with ACKED mode
Once more improve echo-server example
docs: update references page with comment from Timetrade
can: fix request-level API not using encryption for HTTPS requests
routing: add support for `RejectionError`s, closes #259
routing: small cleanup in RequestContext
Stop TcpConnection on handler termination (closes #261)
Merge pull request #264 from hseeberger/master

io: stop TcpConnection on handler termination (closes #261)
io: small improvement in TcpConnection
io: TcpConnection: forward received data to handler immediately without concatenating buffers
docs: improve reference text from TimeTrade with official statement
httpx: make `response` member visible in UnsuccessfulResponseException
io: catch CancelledKeyExceptions in SelectionHandler
http: add missing parsing rules for Location header model
io: upgrade akka.io to latest Akka 2.2 master
Stop TcpConnection on handler termination (closes #261)
io: small improvement in TcpConnection
sbt: upgrade to SBT 0.12.3