Add Player class
Play song implemented
Playback events
Music progress bar
Display like/unlike
Minor apperence change
Play channel
Next command
Validate login callback
Add action and playload to history
Send history
Update DoubanFM API document
Fix bug: stop loading music when execute next command
Implement pause and resume
Implement loop
Improve play information format
Merge branch 'feature/Douban' into develop
Empty login command
Login command flow
Login implemented