Merge branch 'devel' for v2.12

Merge branch 'master' of https://github.com/XavierBerger/RPi-Monitor

Merge branch 'devel' for version 2.10

Cleanup status and statistic menu

Merge pull request XavierBerger#61 from XavierBerger/devel

Version 2.9

Merge pull request XavierBerger#58 from XavierBerger/devel

Version 2.8

Update systemd init script

Fix empty.rrd regeneration bug due to datastore change

Generate empty.rrd at each request to fix issue XavierBerger#23

VERSION 2.5.1 (bugfix)