sync: Check the protobuf version and use the old protoc output if needed. Refs #2017.
tests: In test-chrono-chat, check the protobuf version and use the old protoc output if needed. Refs #2017.
tests: In test-chrono-chat, added method rosterFind because std::find() doesn't compile on some older systems (Ubuntu 12.04). Refs #2017.
tests (minor): In test-chrono-chat.cpp, remove unnecessary std from std::vector and std::string.
Merge branch 'issue/2017-ChronoSync-old-protobuf-support'. Refs #2017.
http://redmine.named-data.net/issues/2017
CHANGELOG: Added Bug fix 2017: Support older versions of Protobuf. Refs #2017.