-check-config will check
  * YAML format
  * OnlineDSN connection
  * TestDSN connection

  add doc for blacklist config

  1. etc/soar.blacklist add `use ?`
  2. blacklist use os.Getwd prefix
  3. update doc

  1. fix -config arg parse bug
  2. code & comment lint

  #5
    Go version large than 1.8 has default GOPATH.
    use `go env GOPATH` get GOPATH envirment variable.

  daily build update
    update vitess vendor package
    update document about installation and configration