bsongen: mysql/proto & some vtgate/proto
bsongen: undoing Nullification till clients are deployed
bson: undo all Null changes till clients are changed
Merge branch 'master' into bson
bsongen: KeyRange
bsongen: tabletserver protos
bsongen: non-string maps & vt/topo structs
bsongen: vtgate & binlog protos
bsongen: go/zk WIP
bsongen: support for custom tags
bsongen: go/zk
bsongen: not ready to be part of main build yet.