That's way better than checking for the OS; psutil may implement it for
new platforms in the future.

As of version 4.3.1, psutil's Process.as_dict() raises ValueError if an
attribute name is invalid.

See e2912943.

config.get_value() already handles NoOptionError in this case.

- wrong continued indentation
- missing whitespace after ':'
- unused imports
- expected 2 blank lines after class or function definition

add gpu plugin shortcuts

[WIP] Add GPU plugin in the WebUI