* will be used in rolling update features
* configured with akka.cluster.app-version
* reusing same implementation as ManifestInfo.Version
by moving that to akka.util.Version
* additional version test
* support dynver format, + separator, and commit number
* improve version parser
* lazy parse
* make Member.appVersion internal
* Add scalafix plugin for jdk 9.
* Add command alias sortImports.
* Excludes some sources from SortImports.
* Update SortImports to 0.4.0
* Sort imports with `sortImports` command.
* 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.
* Major refactoring to remove the need to use special
Cluster instance for testing. Use default Cluster
extension instead. Most of it is trivial changes.
* Used failure-detector.implementation-class from config
to swap to Puppet
* Removed FailureDetectorStrategy, since it doesn't add any value
* Added Cluster.joinSeedNodes to be able to test seedNodes when Addresses
are unknown before startup time.
* Removed ClusterEnvironment that was passed around among the actors,
instead they use the ordinary Cluster extension.
* Overall much cleaner design
* self is initially not member (in gossip state)
* if the join to seed nodes timeout it joins itself, and becomes
singleton cluster
* remove the special case handling of singelton cluster in gossip
merge, since singleton cluster is not the normal state when joining
any more
* Implement the join to seed nodes process
When a new node is started started it sends a message to all
seed nodes and then sends join command to the one that answers
first.
* Configuration of seed-nodes and auto-join
* New JoinSeedNodeSpec that verifies the auto join to seed nodes
* In tests seed nodes are configured by overriding seedNodes
function, since addresses are not known before start
* Deputy nodes are the live members of the seed nodes (not sure if
that will be the final solution, see ticket 2252
* Updated cluster.rst with latest info about deputy and seed nodes
