Keepalives are now used to make sure the remote for the main process does not timeout while the thread remotes do all the work. The error messages for timeouts was also improved to make debugging easier.
* Better messaging for expiration.
* Fixed already stopped message.
* retention-archive and retention-archive-type now use retention-full and 'full' when not specified.
* Fixed issue where backup-user was required (should default to backrest).
* ExecuteTest now supports retries.
* Fixed issue where log test was not comparing test logs.
* Fixed issue where test logs would not match for ssh connection errors
* Major refactoring of the protocol layer to support this work.
* Fixed protocol issue that was preventing ssh errors (especially connect) from being logged.
