Merge pull request #3 from jonsowman/master

Interleaving Etc
error fix
Allow configuring statsfile using env.statsfile.

Set the default to /var/lib/munin/plugin-state/huawei-hg612-munin-output.txt
for safety.

Include a crontab file to be placed in /etc/cron.d.

Update readme to match, and simplify.
Merge pull request #4 from aptivate/master

small improvements