This is a cleaner approach that requires less configuration
in other applications.
This also easily allows us to have another color.
Many checks were made on being exactly at the DEBUG level, they were
fixed to also check on being below DEBUG (i.e. DEBUG_FILTERS).
The browser2 filter debugging is an extra level of "Debug". Since python
logging does not support adding severity levels, we use the Filter class
to remove the lines by default.
Sadly, we cannot pass variable to filters (logging system does not use
the instance passed with addFilter method), so we use to write a filter
for each use case (today: only one...)
I used autopep8 on some files and did carefully check the changes.
I ignored E501,E302,E231,E225,E222,E221,E241,E203 in my search, and at
least E501 on any autopep8 run.
Other style fixes not related to PEP8:
* Only use new-style classes. I don't think the usage of old-style
classes was voluntary. Old-style classes are removed in Python 3.
* Convert an if/else to a one-liner in mediawiki, change docstring style
change to a comment something that wasn't really appropriate for a
docstring.
* Unneeded first if condition in meteofrance
