Color format in detect_live function

[JingWu227]

I used the detect_live function from visualize.py. It reports a blue item as a red one and reports a red item as blue.
Here use openCV to capture video from the camera and directly grab frames to predict.
video = cv2.VideoCapture(0)
ret, frame = video.read()
Since the training set is PIL format and the frames are openCV format, this function should convert the color format from BGR to RGB.