* Re-write InputStreamPublisher as a GraphStage
* Deprecate IOResult.failure and introduce IOOperationIncompleteException
After some dicussion with @johanandren, @raboof and @2m about the
confusion of the materialised value of the IO streams to complete
even if there is an exception (with the exception in the IOResult)
this now changes it to:
* Deprecate failure in IOResult so it is always set to Success(Done)
* Stop using AbrubtIOTerminationException as the inner IOResult also
contains an exception causing confusion
* ⇒, →, ←
* because we don't want to show them in documentation snippets and
then it's complicated to avoid that when snippets are
located in src/test/scala in individual modules
* dont replace object `→` in FSM.scala and PersistentFSM.scala
* Add CopyrightHeader support for sbt-boilerplate plugin.
* Add CopyrightHeader support for `*.proto` files.
* Add regex match for both `–` and `-` for CopyrightHeader.
* Add CopyrightHeader support for sbt build files.
* Update copyright from 2018 to 2019.
