Add a few more details to the cluster client docs.
Merge branch 'master' into more_cluster_client_docs
=act Fix typo in scheduler error message
=doc #3500 Add section about Dependency Injection
=rem #3527 Correction of match in reWatch
Merge pull request #1654 from taylorleese/more_cluster_client_docs

=con Add a few more details to the cluster client docs.
Merge pull request #1669 from oakwhiz/master

=act Fix typo in scheduler error message
Merge pull request #1677 from akka/wip-3500-doc-di-patriknw

=doc #3500 Add section about Dependency Injection
Merge pull request #1678 from akka/wip-3527-wrong-match-patriknw

=rem #3527 Correction of match in reWatch
=act #3525 Retry finishConnect after OP_CONNECT

Patch picked from https://github.com/spray/spray/commit/63648f17807035b4c17b5377ec67f5455a31e5a6
Merge pull request #1681 from drewhk/wip-3504-tone-down-remote-logging-drewhk

+rem #3504: Toned down error logging and made loglevel configurable
Merge pull request #1675 from akka/wip-finish-connect-retries-patriknw

=act #3525 Retry finishConnect after OP_CONNECT
=act, rem, clu #3521: make serialize-messages work with core modules