Refactor code, move settings to python files and add error handlers.

Also, change the console output's implementation to collections.deque.
Update README.org
Update README.org
Update README.org
Add history and fix some bugs. However, the history function doesn't work as I expected.
Merge branch 'master' of github.com:cute-jumper/NerdishDoubanFM

Conflicts:
	DownloadManager.py
	NerdishDoubanFM.py
	Settings.py
	Utils.py