add scheduler to control the download process
complete the qq video url resolution
add the class VideoParameter to get the parameter of video evaluation
add UrlsGenerator class to generate urls from soku site
add log record into the whole project
get the screenshot of video, download all stream type video
modify multithread download method, now the number of thread is based on
the number of video segments. connect the process of url resolution,
video download, screenshot and video parameters getting.
download all sites video.
delete pyc files