Bump cloudfoundry/warden:
  Alex Choi and Maria Shaldibina:
     Make sure stop process times out
  Maria Shaldibina:
     Update README.md
  Alex Suraci and Chris Brown:
     reimplement finding the mountpoint of a directory
  Maria Shaldibina and aram price:
     Add contributing guide
     Add testing instructions
Bump cloudfoundry/warden:
  Alex Suraci and Chris Brown:
     remove ffi/sys-filesystem dependencies ( Travis Unknown )