Add main CLI function and library function for getting segment times

[montanaflynn]

• Adds a main program with options

    parser.add_option("-v", "--video", default="./videos/FrG4TEcSuRg.mp4", help="Which video to process")
    parser.add_option("-d", "--duration", default=3, help="Duration of the segments", type="int")
    parser.add_option("-t", "--top", default=5, help="How many top segments to get", type="int")
    parser.add_option("-b", "--bottom", default=0, help="How many bottom segments to get", type="int")

• Adds a new function in the library get_scored_segments

    @param video_path: video to run gif segment scoring on
    @param duration: duration of segments
    @param top_k: count of top gifs to return
    @param bottom_k: count of bottom gifs to return
    @return: (good_gifs, bad_gifs)