* ⇒, →, ←
* 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.
* also improved fault handling in various places (bugs found)
* and manually triggered Update must be distinguished from scheduled
auto updates, otherwise manual Update will schedule extra auto updates
* remove channels
* remove View
* remove Processor
* collapse the complicated internal state management
that was spread out between Processor, Eventsourced and Recovery
* remove Recovery trait, this caused some duplication between Eventsourced
and PersistentView, but but the enhanced PersistentView will not be based
on recovery infrastructure, and therefore PersistentView code will be replaced anyway
* remove PersistentBatch
* remove LoopMessage
* remove deleteMessages of individual messages
* remove Persistent, PersistentRepr and PersistentImpl are kept
* remove processorId
* update doc sample code
* note in migration guide about persistenceId
* rename Resequencable to PersistentEnvelope
* also remove final of around methods, and let deliver send when not recoveryRunning
(cherry picked from commit 312b0d107a179accaf135f64ed9c3b78f3e351d1)
