Merge tag 'v2.1.2' into develop

Version 2.1.2
Prepare repos for new version
Add short key '2' (or --disable-left-sidebar option) to hide the left sidebar
Verbose message if the MatPlotLib lib is not installed - issue #428
Add a configuration key to set the gaph ouput folder --output-history - issue #428
Add Network, FS, diskio to the graph generation feature
Complete graph history feature #428
Disable process stat extended by default (issue #430)
Anothers try/except for NoSuchProcess (issue #414 and #432
Add a key ('F') and a command line option (--fs-free-space) to display FS free space instead of used space (issue #411)
Correct issue #433 on battery percent update
Python3 compliance for decorator
Add building block for the Zroconf protocol
--append
Correct issue #414
Another catch for NoSuchProcess - Correct issue #414
Fix incorrect log file path in doc
Fix misspelling in process list
Merge pull request #435 from desbma/develop

Minor cosmetic fixes

Merci pour la contrib ;)
Fix incorrect log file path in doc