- remove obsolete code
- glances_password: update comments and fix typos
- re-apply fix to avoid string format conflicts (screwed up after
  feature branch merges)
- strip trailing whitespaces
- flake8

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

Mandatory only for multi-line continuation

Explicit is better than implicit.

Client/Server works but no process are displayed. Also rename In/Out by Read/Write for DiskIO according to #339