Revert "Tune Time-To-Live for DNS records, ttl=300s"

It doesn't make sense to set it that low.

This reverts commit 5c782e3af2e02af6259dcc69bab52daa776fde29.
Enable notify in the master zone

Just to make sure that the slaves get notified.
Set more sensible timeout values

These values were way off. Especially a retry higher than TTL does
not make sense..
Make sure that the master node has slaves_names/ips set

Without the dup, it deletes the master node from the nodes.each
loop below, so it doesn't set anything..
Merge pull request #114 from dirkmueller/master

Multi-DNS fixes