Improvement/3.x/sessionreplication loggingcleanup

- the debug parameter is dropped. The only thing it does is change the loglevel, but that can just as easily
be configured by setting the loglevel for the session replication. That is the traditional way to see what
is going on inside an application.

- improved logging messages

- log statements that generate new strings, are fronted with a log.islevelenabled check to prevent
unwanted stringconcatination

- some minor code cleanup