SMART plugin

S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) plugin for Sensu
change extension
change config file search path
display device name in error message
sudo added to smartctl command
print booth warnings and criticals if there is critical error
put level into error message
Attribute id into error message
rubocop errors corrected
Merge pull request #390 from tarhelypark/master

SMART plugin