get hash strings of arbitrary data structures

 structhash is a Go library for generating hash strings of arbitrary
 data structures. Features
  - fields may be ignored or renamed (like in json.Marshal, but using
    different struct tag)
  - fields may be serialized
  - fields may be versioned
  - fields order in struct doesn't matter (unlike json.Marshal)
  - nil values are treated equally to zero valuesInstallation