Munin contributed plugins

Unify more author names with special characters

Additionally an ambiguous line in the "author" section of a plugin was
removed in order to avoid confusion for the Munin Plugin Gallery parser.

[plugins/weather/wunderground] Add plugin to query station data from Weather Underground

It's a bit backwards, but works a treat when you don't own the station
but want the data in a better format.

Includes warnings on UV and heat indices, and visible lines for wind...

Port some python2 plugins to python3

Plugins weather_*: specify regular expressions as raw strings

New versions of flake8 already complain about the non-raw nature of the
strings (respectively the improper escaping in the regular expression).

Whitespace cleanup

• remove trailing whitespace
• remove empty lines at the end of files