* ⇒, →, ←
* 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.
* to avoid OversizedPayloadException
* some complex deltas grow for each update operation, e.g.
when updating different keys in ORMap (PNCounterMap)
* such large deltas can safely be discarded and disseminated as full
state instead
* added ReplicatedDeltaSize interface to be able to define the "size"
and when that size exceeds configured threshold the delta is discarded
