1.8.0

• make empty-body-handling consistent between chunked requests
  • empty json produces {}
  • empty raw produces new Buffer(0)
  • empty text produces ''
  • empty urlencoded produces {}
• deps: qs@2.2.3
  • Fix issue where first empty value in array is discarded
• deps: type-is@~1.5.0
  • fix hasbody to be true for content-length: 0