Merges Zone and ZoneInfo. Adds implementation of Dns.#629

Merged

aozarov merged 4 commits intogoogleapis:dns-alphafrom

mderka:rpc-default

Feb 9, 2016

Commits on Feb 7, 2016

Commits on Feb 8, 2016

Included options attribute to Zone. Fixed symmetry of toPb and fromPb.
mderka
committed

Commits on Feb 9, 2016

Removed zone.get() and optimized retries.
mderka
committed