Change DnsCachedResolver interface to return records in vector rather than list
Change resolver to return multiple targets, and change blacklisting to greylisting
Merge branch 'master' of github.com:Metaswitch/cpp-common into sto645
Fix bug which could cause resolver to return too many targets when doing SRV resolution
Fix bug that results in SRV resolver not returning enough servers
Fix DNS TTL handling
Merge remote-tracking branch 'origin/master' into sto645
Don't cache failure responses
Merge pull request #72 from Metaswitch/sto645

Updates to BaseResolver to return multiple servers on a single resolve call