Code cleanup
Fix a bug in RootDSEBackend.getRootDSE().

RootDSEBackend.java:
In getRootDSE(), fix a bug with supportedAuthPWSchemes which wrongly referred to supportedSASLMechanism attribute.
In addAttribute(), renamed publicNamingContextAttr parameter to attribute
Used interfaces for collections rather than concrete classes.
Removed useless @inheritDoc javadoc.

Task.java:
Extracted methods getTime(), compareTimes(), 
In execute(), simplified code.

LDAPReplicationDomain.java, ReplicationDomainMonitorData.java:
Code cleanups