smartlib: add DVS plugin based on opencv stabilizer

 * enable libxcam smartlib DVS plugin
 * add Opencv DVS abstract layer
 * test commandline:
  $ gst-launch-1.0 filesrc location=test.mp4 ! videoparse width=1920 \
    height=1080 format=nv12 ! xcamfilter copy-mode=1 buffercount=32 \
    enable-warp=1 ! queue ! vaapih264enc rate-control=cbr ! \
    qtmux ! filesink location=test_dvs.mp4

Signed-off-by: Wind Yuan <feng.yuan@intel.com>
11 files changed