Merge commit '303fadf5963e01b8edf4ba2701e45f7e9e586aeb'

* commit '303fadf5963e01b8edf4ba2701e45f7e9e586aeb':
  avconv: Document the -init_hw_device option
  avconv: Enable generic hwaccel support for VDPAU
  lavc: vdpau: add support for new hw_frames_ctx and hw_device_ctx API
  lavc: Add hwaccel_flags field to AVCodecContext
  avconv: Enable generic hwaccel support for VAAPI
  avconv: Generic device setup
  hwcontext: Make it easier to work with device types
  hwcontext: Add device derivation

This commit is a noop, see
b22172f6f3530b8bd9d1d2c38a31b1e9c3729e42
0b1794a43e1083644aa3db2a09323681cfe080ec
06043cc0bc72b530db352a67776392cf61a54104
be510733523016aae7dca74bba6aa3b223c1fed6
156bd8278f4098426cffaa68efb161907e5c1869
7e4ba776a2240d40124d5540ea6b2118fa2fe26a
e462ace84b92e54d2a5fa651d6469aefe0f1efbf
527a1e213167123d24d014bc0b956ef43d9d6542

Merged-by: James Almer <jamrial@gmail.com>