[system_profile] created a system_profile extension to produce metrics from /proc/*
[system_profile] added /proc/loadavg 1, 5, and 15 min
[system_profile] added /proc/net/dev for network metrics
[system_profile] added /proc/meminfo for memory/swap metrics
[system_profile] change default chunk size to 4096
[system_profile] added header
Merge pull request #488 from portertech/system_profile

Created a system_profile extension, /proc/* metrics