jeffjiang: add cfgclient and customruleclient interfaces so that custom rule and other configurations may be retrieved from plugin mechanism and Zookeeper-like services
Merge remote-tracking branch 'upstream/master'
jeffzjiang: split QueryRules into three namespaces
jeffjiang: split current mixed QueryRules into three isolated ones
jeffzjiang: fix style issues
jeffzjiang: fix style issues
add synchronization to SqlQuery.GetQueryRules/SetQueryRules to avoid race condition
Remove ZK paths suport names in vtctl commands

1. ZK path is resolved in methods tabletParamToTabletAlias,
   shardParamToKeyspaceShard and keyspaceParamsToKeyspace.
   Therefore, all of them are refactored to not accept ZK path
   and return error if do so.
2. Move vtPathToCell and keyspaceParamToKeyspace to
   vt/vtctl/plugin_zktopo.go since they contains zk
   logic only.
3. Remove resolveWildcards method in vtctl.go
4. Remove most zk stuff in command description
jeffjiang: split query rule informations from SchemaInfo into QueryRuleInfo structure
jeffjiang: split query rule informations from SchemaInfo into QueryRuleInfo structure
Add tracing for refreshTablet and action unlock.
jeffjiang: fix code styles and add sanity check for QueryRuleInfo.SetRules
Now using Context in Wrangler. Experimenting with Ping.
Also refactoring Validate commands to be simpler.
Merge branch 'master' into replication
jeffjiang: fix customrule test such that it can detect failure to match custom rules
Merge pull request #204 from yaoshengzhe/fix_remove_zk_vtctl

Remove ZK paths suport names in vtctl commands
Merge pull request #210 from youtube/replication

Replication
jeffjiang: add test for QueryRuleInfo, fix existing QueryRule test and add sanity check for QueryRuleInfo.GetRules
Now using context everywhere for tm interactions.
Merge pull request #209 from youtube/trace

Add tracing for refreshTablet and action unlock.