Feature/process plugin fixes

The actual bug fix (plugin not returning data) is around line 40.  The logging level change around line 148/152 is to address "mon-agent user agent does not have access to I/O counters" errors, as the mon-agent user may not have permission to access this data for some processes, like mysqld.

The rest is PEP8 stuff, mostly getting the line length down below 80 characters.