Document failure mode

[saschat]

From what I understand failureMode=true is what other clients call failover=false in the sense that if failure mode is on, the client does not failover to other servers but marks the failed server as dead until it come back up. This is confusing.

In the short term this should be documented. In the long term a configuration like builder.setFailover(true) could be added that sets failureMode=false.

@killme2008 If you don't mind I will submit a PR with some documentation.

[killme2008]

PR is welcome, thanks for your suggestion.