Add video API

Core/build.xml

...g/sleuthkit/autopsy/report/video/VideoSnapShotWorker.java

Core/src/org/sleuthkit/autopsy/report/video/VideoUtilis.java

thirdparty/ffmpeg/avcodec-59.dll

thirdparty/ffmpeg/avdevice-59.dll

thirdparty/ffmpeg/avfilter-8.dll

thirdparty/ffmpeg/avformat-59.dll

thirdparty/ffmpeg/avutil-57.dll

thirdparty/ffmpeg/ffmpeg.exe

thirdparty/ffmpeg/postproc-56.dll

thirdparty/ffmpeg/swresample-4.dll

thirdparty/ffmpeg/swscale-6.dll