Simple Process Check plugin fix

- https://github.com/scoutapp/scout-plugins/commit/284dac83da9b135b98a18c52f328d07fe17dd37c
broke this plugin on new installs

- The issue has been fixed and the code is much simpler with the same
  results
SPC Plugin PID filtering fix

After reviewing the PID filtering, I noticed it would not work as-is.
The update should now fix PID filtering in addition to the previous fix.
Merge pull request #139 from willdrew/master

Changing the logic for current process exclusion. Existing installs not using process exclusion will work the same. Existing installs using process exclusion should change the ps_command option to ps -eo comm,args,pid