* add OverlapChecker, move the test of overlap AFTER the directive setup process, change key of configs to allow multiple same key

* glitch when rebase. init of Config should include the default host

* add tests for the registering of configuration
rename multicast in 'unbound'.
add comments on the validator

* - merged zoneAddr and addrKey that are very similar
- move maps of Validator to zoneAddr, avoinding need to have string representation of zoneaddr
- moving key build for saving Config at Config side instead of dnsContext

* - UT on saving config is now useless.

* - cannot cleanup access to Configs after setup. Deferred function to Start, use it

* - cleanup register unit tests. remove useless function

* - address comments of review. name of validator, comments, simplify registerAndCheck

* - fixes after review. renaming a function and a comment