packet cache improvements for recursive answers
- fix tagging of recursive packets
- age ttl in packet cache for recursive results
- respect allow-recursion in packet cache
catch non-fatal exceptions in control listener loop
Merge pull request #1415 from mind04/bindcrash

catch non-fatal exceptions in control listener loop
Merge pull request #1414 from mind04/packetcache

packet cache improvements for recursive answers
actually honour disabled (from json) during zone2sql for mysql or oracle
fix uninitialised values in bind backend