init
aaaa
format
show article file.
add the task bug
fix about download progress update issue.
1. add the article date time. local article can sort by date.

2. seekbar need can seek to position; drag the seekbar can jump the correct position.

3. play/pause button switch.

4. play next or play backward.
indicate the now playing article on the channel list view activity.
1. clear the media player instances after exit app.

2. clear the current playing article after exit the app.
delete the useless file.
fix the issue about article has no audio.
add the sync lrc view.
add the delete file function.
add the loop mode.
modify for the image in the article.
modify the version
Merge branch 'master' of https://github.com/chriscuihuawei/voaEnglish