* Move NodeCollector into package collector
* Refactor collector enabling
* Update README with new collector enabled flags
* Fix out-of-date inline flag reference syntax
* Use new flags in end-to-end tests
* Add flag to disable all default collectors
* Track if a flag has been set explicitly
* Add --collectors.disable-defaults to README
* Revert disable-defaults flag
* Shorten flags
* Fixup timex collector registration
* Fix end-to-end tests
* Change procfs and sysfs path flags
* Fix review comments
* Implement commonalities and linux support for ARP collection
* Add ARP collector to fixtures and run as part of e2e tests
* Bubble up scanner errors
* Use single return values where it makes sense
* Add missing annotation
* Move arp_common into arp_linux
* Add license header to arp_linux.go
* Address initial feedback
* Use strings.Fields instead of strings.Split
* Deal with scanner.Err() rather than throwing away errors
* Check for scan errors in-line before interacting with the entries map
* Don't interact with potentially empty text from scan
* Check for scan errors outside the scan loop
* Add comment about moving procfs parsing
* Add more direct comment
* Update initialism style to match go style guide
* Put function args on the same line
* Add TODO in front of comment about procfs extraction
* Guard against strings.Fields returning an empty slice
* Be more defensive about ARP table format and use upcase more broadly
* Enable the ARP collector by default
* Add ARP collector to the README
* Remove 'entry'
