make isMaster ip check more tollerant for different ipv6 notations

::1 and 0::1 now match

fixes #1174
make notification queue ipv6 compatible
add direct-dnskey to doc
don't addSuckRequest after supermaster zone creation to avoid simultaneous AXFR for the new zone.
prevent duplicate slave notications caused by different ipv6 address formatting
aviod address truncation in doNotifications
add toMasks and clear to NetmaskGroup class and use it
add only-notify option
fixes #454
closes #778
partial fix #949
add also-notify option
fixes #949
catch ComboClass exceptions in communicator