Add args visibility to the plugins to handle with the SNMP server properties (address, community...)

Highlight the nice value of a process when is different from 0.
Add 'NICE' decoration for managing color.

It's now possible to define specific colors for both process name and
process status.

Neither regex, nor str.find() were used. Yeah!

The regex makes Glances crash when the system is under heavy load,
e.g., during compilation of packages.

This reverts commit 565ec32f.

Mandatory only for multi-line continuation

Explicit is better than implicit.