Change package provider to pip

1. use upstart to manage service.
2. use pip instead of apt to use a newer version of supervisor.
3. add killasgroup and stopasgroup options.

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FYI, I only tested it on Ubuntu.

The package from default apt provider is 3.0a8 which is a little old and don't have killasgroup/stopasgroup options. So I made a little refine to use pip as provider.

I'm not familiar with other OS so I choose to use upstart which is the recommend way for ubuntu, and it may not work for other OS. So it may need some other tweaks before merge, just a suggestion here.