Interrupt Collector and Parser

Changes: (The major ones are really for `/proc/interrupts`)

1. Collector updated:
  * Collector for `cpuusage` and `cpuhz` updated to collect per core rather than aggregated.
  * Collector for `top` updated to have `-c` flag so can see command used to generate process.
  * Collector for `/proc/interrupts` added so can get interrupts per core and IRQs.
  * Collector for `netstat -s` added to collect `netstat` statistics.
2. Parser Metric for `/proc/interrupts`.
3. Added log example for `/proc/interrupts` with a configuration file example.
4. Updated example logs for `sar.cpuusage.out` and `sar.cpuhz.out` to be per core now.

Is it more for readability and maintaining? Adding an extra function call for a quick string check seems a bit much. Just wondering why would be considered "really  not a good idea".