hevc: prefix width and height SPS variables
hevc: remove duplicated code
hevc: ignore def_disp_win only when it's respected
hevc: fix default display window parsing (thanks Yasuke)
hevc: add a generic output_window to siplify cropping
hevc: Support bitstream encapsulated as 14496-15 format.

Conflicts:
	libavcodec/hevc.c
	libavcodec/hevc.h
mov: Support HEVC demuxing.
matroskadec: Support HEVC demuxing.
hevc: Set the maximum num_reorder_pics to AVCodecContext.has_b_frames.

Output frames after the num_reorder_pics so that num_reorder_pics==0
outputs frames immediately.
hevc: Add max_sub_layers to HEVCSPS to simplify setting has_b_frames.
Merge remote-tracking branch 'koda/hevc_upstream' into hevc_upstream
Merge branch 'hevc_upstream' of https://github.com/OpenHEVC/libav into hevc_upstream